Since 1921,the Communist Party of China（中国共产党）has been leading the Chinese people a better life.（ ）
A．ofB．onC．atD．to
We should do everything to protect the earth， we'll lose our home．（ ）
A．orB．soC．and
﹣How did the accident happen？
﹣The girl Wechat（微信）while walking across the street．（ ）
A．readsB．is reading
C．was reading
As students，we ought to the act of cheating in the exams．（ ）
A．provideB．preferC．prevent
﹣ do you go to see your grandparents？Once or twice a week？
﹣Once a week．（ ）
A．How soonB．How oftenC．How long
David felt because he was not able to get a ticket to the concert．（ ）
A．movedB．excited
C．disappointed