a. He is confident to get a scholarship.

Ans: He is confident of getting a scholarship.

b. My car is inferior and less costly than yours.

Ans: My car is inferior to and less costly than yours.

c. He talks as if he knows everything.

Ans: He talks as if he knew everything.

d. Many people died by the explosion.

Ans: Many people died in the explosion.

e. The number of boys are increasing day by day.

Ans: The number of boys is increasing day by day.

f. It rained heavily in the morning, wasn't it?

Ans: It rained heavily in the morning, didn't it?

g. The rice of Bangladesh is better than Burma.

Ans: The rice of Bangladesh is better than that of Burma.