You are going on a short holiday soon and would like to invite a friend to join you. Write a letter to him/her and say– Explain why you need a holiday.– Explain why you want your friend to come.– Where and when do you want to go?

Grammar and spelling errors:
Line 3, column 103, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: I'm
...you to join me on a short holiday which Im planning to go. I am planning to go ...
^^
Line 5, column 178, Rule ID: ENGLISH_WORD_REPEAT_BEGINNING_RULE
Message: Three successive sentences begin with the same word. Reword the sentence or use a thesaurus to find a synonym.
...tly visit it in January 2019, 2nd week. I would like to mention that you should r...
^
Line 7, column 20, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: I've
... enjoy the snow. From last18 months Ive been working constantly and need a brea...
^^^
Line 7, column 251, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: I've
...ould surely join me on this holiday and Ive attached some photographs of our destin...
^^^
Line 9, column 128, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...r the travel and hotel booking on time. Best, Anushka
^^^^^

Transition Words or Phrases used:
really, so, well

Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments

Performance on Part of Speech:
To be verbs : 4.0 7.48453608247 53% => More to be verbs wanted.
Auxiliary verbs: 9.0 4.92783505155 183% => OK
Conjunction : 5.0 5.05154639175 99% => OK
Relative clauses : 7.0 3.03092783505 231% => Less relative clauses wanted (maybe 'which' is over used).
Pronoun: 30.0 32.9175257732 91% => OK
Preposition: 21.0 26.3917525773 80% => OK
Nominalization: 2.0 3.85567010309 52% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.

Performance on vocabulary words:
No of characters: 803.0 937.175257732 86% => OK
No of words: 174.0 206.0 84% => More content wanted.
Chars per words: 4.61494252874 4.54256449028 102% => OK
Fourth root words length: 3.63192868298 3.78020617076 96% => OK
Word Length SD: 2.45590656939 2.54303337028 97% => OK
Unique words: 109.0 127.690721649 85% => More unique words wanted.
Unique words percentage: 0.626436781609 0.622605031667 101% => OK
syllable_count: 242.1 290.88556701 83% => OK
avg_syllables_per_word: 1.4 1.41237113402 99% => OK

A sentence (or a clause, phrase) starts by:
Pronoun: 6.0 9.13402061856 66% => OK
Article: 0.0 0.824742268041 0% => OK
Subordination: 0.0 1.83505154639 0% => More adverbial clause wanted.
Conjunction: 0.0 0.463917525773 0% => OK
Preposition: 1.0 1.44329896907 69% => OK

Performance on sentences:
How many sentences: 8.0 12.6804123711 63% => Need more sentences. Double check the format of sentences, make sure there is a space between two sentences, or have enough periods. And also check the lengths of sentences, maybe they are too long.
Sentence length: 21.0 16.3608247423 128% => The Avg. Sentence Length is relatively long.
Sentence length SD: 51.1362257137 44.8134815571 114% => OK
Chars per sentence: 100.375 76.5299724578 131% => OK
Words per sentence: 21.75 16.8248392259 129% => OK
Discourse Markers: 2.0 4.34317383033 46% => More transition words/phrases wanted.
Paragraphs: 4.0 4.29896907216 93% => OK
Language errors: 5.0 2.54639175258 196% => OK
Sentences with positive sentiment : 6.0 7.41237113402 81% => OK
Sentences with negative sentiment : 0.0 1.49484536082 0% => More negative sentences wanted.
Sentences with neutral sentiment: 3.0 3.94845360825 76% => OK
What are sentences with positive/Negative/neutral sentiment?

Coherence and Cohesion:
Essay topic to essay body coherence: 0.291601285956 0.216113520407 135% => OK
Sentence topic coherence: 0.118618228498 0.0766984524023 155% => OK
Sentence topic coherence SD: 0.118411840121 0.0603063233224 196% => OK
Paragraph topic coherence: 0.18291375598 0.12726935374 144% => OK
Paragraph topic coherence SD: 0.136322671016 0.0580467560999 235% => More connections among paragraphs wanted.

Essay readability:
automated_readability_index: 11.2 8.37731958763 134% => OK
flesch_reading_ease: 67.08 70.7449484536 95% => OK
smog_index: 3.1 3.82989690722 81% => OK
flesch_kincaid_grade: 9.1 7.45979381443 122% => OK
coleman_liau_index: 9.46 8.71597938144 109% => OK
dale_chall_readability_score: 7.31 7.59969072165 96% => OK
difficult_words: 29.0 41.2886597938 70% => More difficult words wanted.
linsear_write_formula: 10.5 8.62886597938 122% => OK
gunning_fog: 10.4 8.54432989691 122% => OK
text_standard: 11.0 8.15463917526 135% => OK
What are above readability scores?

---------------------
Rates: 73.0337078652 out of 100
Scores by essay e-grader: 6.5 Out of 9
---------------------
Note: the e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.

"More adverbial clause wanted. "

I did not understand this Point. Please explain for this writing task"https://www.testbig.com/ielts-writing-task-i-ielts-general-training-ess…"

An adverb clause is a group of words that function as an adverb in a sentence. The clause can modify or describe verbs, adverbs, and adjectives. In general, adverb clauses add information that elaborates on when, where, why, how, how much or under what condition the action in the sentence takes place.

An adverb clause isn't just any group of words, however. A clause must contain a subject and a verb to be complete. An adverb clause also begins with a subordinating conjunction, such as "after," "if," "because" and "although." If you see a group of words in a sentence that acts like an adverb but does not have both a subject and a verb, it's an adverb phrase.
Using Adverb Clauses

Using an adverb clause in your sentence is a good way to add important, descriptive detail and information to your writing. They are flexible and can be placed at the beginning, middle or end of a sentence, depending on where it sounds best.

Adverb Clause at the Beginning of a Sentence

When placed at the beginning of a sentence, an adverb clause is followed by a comma, as seen in these examples of adverb clauses:

Whether you like it or not, you have to go to bed now.
If you pay your bills on time, you can have a good credit score.
Unless you run fast, you will miss the bus.
Because he loved her, he didn't believe she was having an affair.
Once they saw the car coming, the birds flew away from the road.
Although she has a business degree, she is working as a retail clerk.
As we bought the tickets, the overture was beginning.
Before we go on vacation, we must make reservations
Since I'll be working late, I'll eat downtown.
Now that everyone has left the party, we need to start cleaning.
Unless you put in more hours, I cannot recommend you for the promotion.
As soon as I saw you, I knew something was wrong.

Adverb Clause in the Middle of a Sentence

When placed in the middle of a sentence, an adverb clause is offset by commas. Note that this is an unusual placement that indicates an interruption of the main thought:

My sister, when she is angry, will turn red in the face.
Elephants, although they are large, are not predators.
Chocolate, because it has a low melting point, can be difficult to bake with.
He remembered, after he left the house, that he needed to mail the thank you cards.

Adverb Clause at the End of a Sentence

When placed at the end of the sentence, an adverb clause needs no additional punctuation:

Marty kept his schedule open in case his wife went into labor.
You must keep practicing the song until you get it right.
Give us a call when you get back from your trip.
We need to find the bar where they asked us to wait.
The fireworks show will start after the sun goes down.
The cat made herself at home in the apartment as if she had always lived there.
Frank ran the race as though his life depended on it.
We can swim in the pool as soon as you put on sunscreen.
I never knew how wonderful life could be until I met you.
You need to remain calm even if everyone else panics.
The day felt long because we had nothing to do.
I won't allow you to see that movie even though you are old enough to go.
We can get some new clothes as long as the store is open late.