1 . The chemical________ of rainfall changes slightly as rain clouds move.

A．compose

B．confirm

C．concern

D．composition

2 . ________ confidence in yourself is the biggest difficulty ________ greater progress in your work.

A．Lacking of; in making	B．Lack of; to make
C．Lack of; in making	D．The lack of; to make

3 . ________is very important in our everyday life.

A．Greet

B．Greeting

C．Greetings

D．Greets