Mrs. Smith found the toys here and there, so she asked her son to ______ his toys before having dinner

_____can work out the problems because _____of the problems is easy.

Do you have________ books on Chinese food?—Yes, I have______.

Is ____ necessary to complete the design before National Day?

May I speak to the headmaster?—He’s not here．He _______ Beijing．Can I take a message?