1 . —Mom, where should I put the food for David?
—Oh, put it on the table and ______ it with a bowl to keep it from getting cold.

A．cover

B．fill

C．mix

D．add

2 . After boiling the noodles, ________ (添加) some vegetable to the noodles.

3 . Peter tasted his coffee, and then ________ (add) some milk.

4 .

9 . In the last stage of making a cartoon sounds effects, like the noise of the underground, must __________ (add) separately.