It worried her a bit ________ her hair was turning gray.

A. while

B. that

C. if

D. whether

He doesn't know ________ is ________ he was born.

A. that; where

B. that; what

C. where; that

D. what; where

________ there is life on another planet is almost impossible.

A. How

B. That

C. Why

D. Whether

Can you imagine what a girl will look like ________ she comes across a rat in her room?

A. now that

B. though

C. in case

D. if

________ is the most useful invention?

A. Do you think which of these

B. Which of these do you think

C. Which of these you think

D. You think which of these

The question he asked was ________ the electrical equipment should be stored.

A. what

B. which

C. where

D. because

________ proves that my advice is right.

A. It will happen that

B. That has happened

C. What has happened

D. When it happened

Perseverance is a kind of quality—and that's ________ it takes to do anything well.

A. what

B. that

C. which

D. why

There's a feeling in me ________ we'll never know what a UFO is.

A. that

B. which

C. of which

D. what

—Are you still thinking about yesterday's game?

—Oh, that's ________.

A. what makes me feel excited

B. whatever I feel excited about

C . how I feel about it

D. when I feel excited