________ under the tree? No，they aren’t.
A．Where are      B．Are they       C．Is it

________ my baseball? It’s under the chair.
A．Where       B．Where’s      C．Where are

--_______ do you visit your grandparents?
--Two or three times a month.
A. How long      B. How many       C. How often

A: __________ do you use your computer?
B: I use it in the evening.

Some of the students are nearsighted______they spend too much time watching TV or playing online games.

Smile to the world, ________ the world will smile back to you.

I don’t know _____ or not he will come . _______ he comes , I will call you .

He was _______ pain, __________ he didn’t cry.

—Do you like math?
—Yes, it’s difficult ________ really interesting.

The art club is for members only. You can’t go in ____ you are a member.