单选题：—What are you doing there? —I am tasting the soup. It ____..

All the books in the list, _____ otherwise stated, will be available.A. as B. ifC. unless D. although

He was so busy that _____ I could say hello to him he had rushed out of the room.A. when B. beforeC. since D. until

— Professor Smith, some students want to have a talk with you. ___ they wait here or outside?— Show them in now, please.A．Will B．ShallC．WouldD．Must

Sir, you _______ be sitting in this sitting room. It is for women and children only.A．oughtn’t toB．can’tC．won’tD．needn’t

It's quite a time _____Liu Xiang was injured in the foot, but we're sure it won't be long _____he returns tothe track.A. after; when B. before; since C. that; when D. since; before