He gave me many good advices. (Improve)

• A. much good advices
• B. much good advice (Answer)
• C. many good advice
• D. No improvement

'Advice' is uncountable. It has no plural form. Use 'much advice' or 'a piece of advice'.

She made him to wait for two hours. (Improve)

• A. made him waited
• B. made him wait (Answer)
• C. made him waiting
• D. No improvement

Causative 'make' is followed by a bare infinitive (without 'to'): make someone do.

The furniture are new. (Improve)

• A. furnitures are
• B. furniture were
• C. furniture is (Answer)
• D. No improvement

'Furniture' is an uncountable noun and takes a singular verb.

She is more taller than her sister. (Improve)

• A. most tall
• B. taller (Answer)
• C. more tall
• D. No improvement

'Taller' is already comparative. Adding 'more' creates an incorrect double comparative.

He did not say nothing about his plan. (Improve)

• A. did not say anything (Answer)
• B. did not say something
• C. said not nothing
• D. No improvement

Double negatives are wrong in Standard English. 'Did not say anything' is correct.

She was so depressed that she could not hardly speak. (Improve)

• A. could not speak
• B. could hardly speak (Answer)
• C. could not hard speak
• D. No improvement

'Hardly' itself carries negative meaning. Adding 'not' creates a double negative. Use 'could hardly speak'.

He is one of the sincere worker in the office. (Improve)

• A. most sincere worker
• B. one of the sincere workers (Answer)
• C. a most sincere worker
• D. No improvement

'One of the + plural noun' is the correct structure.

I have a tendency to speak English grammatically wrong. (Improve)

• A. grammatically wrongly
• B. grammatically incorrect
• C. grammatically incorrectly (Answer)
• D. No improvement

An adverb modifies a verb. 'Incorrectly' (adverb) modifies 'speak'. 'Wrong' is an adjective.

He insisted that I should drink the water. (Improve)

• A. insisted that I must drink
• B. insisted on my drinking (Answer)
• C. insisted that I ought to drink
• D. No improvement

'Insist on + possessive + gerund' or 'insist that + subject + should + verb' are both acceptable, but option B is most precise.

Let you and I decide the matter. (Improve)

• A. Let you and me (Answer)
• B. Let us and I
• C. Let I and you
• D. No improvement

After 'let', use objective case 'me', not nominative 'I'.