﹣Where were Bill and David when the teacher came in？
﹣They in the hallway．（ ）
A．are talkingB．have talked
C．were talkingD．talk
Many scientists believe that robots ______ able to talk like humans in 50years．（ ）
A．wereB．areC．will beD．have been
Why does the earth look blue in space？
Because most of the earth's surface ______ by water．（ ）
A．coversB．is covered
C．coverD．are covered
Look! The model is walking to us．______ nice dress!（ ）
A．WhatB．What aC．HowD．How a
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