With an appropriate unit noun:

(1)Part of the lake has been polluted. You can see the water is covered with a ________ of oil.

(2)Let me give you a ________ of advice.

be-subjunctive

collective nouns

determiners

antecedent

What is given information and what is new information?

Explain the relationship between tense and time.

Using inversion:

I have never been there before.

Using a YES-NO question:

I have already finished the assignment the teacher gave us last week.

Reinforcing the negation:

These goods are not satisfactory.

Using a non-finite form.:

Don't take his words seriously if he professes that he knows everything about your history.