Can I use your dictionary，Grace？
Sure．But you return it after class．（ ）
A．canB．mustC．may
What were you doing ______ I knocked at the door？
I was sleeping．（ ）
A．unlessB．onceC．whenD．while
Mount Xiaolei is not far away from here，but it will still take us a few hours ______ there by bike．（ ）
A．gettingB．to getC．gotD．get
Hi，Sara．Is this ______ English book？
No．______ is on the desk．（ ）
A．your； MineB．your；MyC．yours；MineD．your；My
It is necessary ______ us to help our friends out when they meet difficulties．（ ）
A．toB．ofC．withD．for
What did you do last night，Bob？
First I did my homework，and then I played ______ piano for half ______ hour．（ ）
A．the；aB．/；anC．the；anD．a；the