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1. He dances as good as she dances.

2. He dances as good as she danced.

3. He dances as good as she has danced.

4. He dances as good as she has been dancing.

5. He dances as good as she is.

Hello Grammar Teacher/Teachers,

a. Are all the sentences grammatically correct ?

b. Is the fifth sentence similar to the first sentence,that is,the comparison is to her dancing at any time ?

Thank you.

With best wishes.
Comments  
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These are OK:

1. He dances as good as she dances.

2. He dances as good as she danced.

3. He dances as good as she has danced.

4. He dances as good as she has been dancing.
5 is no good.

PS: I forgot to add that well is much better than good, which is only casual English.
Sentence A. He dances as well as she is.

Hello Grammar Teacher,

I would like to thank you for your advice. I have changed 'as good as ' into ' as well as ' .According to your reply, the last sentence ( He dances as good as she is .) is no good.

However, I do not understand the reason of your criticism. Could you explain it ?

Is Sentence A elliptical ? If no, what does ' she is ' mean ? If yes , what is the missing word(s) after 'she is ' ?

Thank you.

With best wishes.
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Q5 is wrong because 'she is' is not elliptical of any grammar that could fit in the sentence-- it means nothing.
But you could say "He is dancing as well as she is," meaning, "as well as she is dancing"

or you could say

"He dances as well as she does."
It has nothing to do with 'casual' English, there is no such thing. 'Good' is an adjective, and 'well' is an adverb, so it is incorrect to use 'good' in these sentences.

Ex-English teacher.
Students: Are you brave enough to let our tutors analyse your pronunciation?
Anonymous it is incorrect to use 'good' in these sentences.
I can see why you are an ex-teacher.