The fact has worried many scientists_______ the earth is becoming warmer and warmer these days.
A. what B. which C. when D. That
Seeing the happy ______ of students playing basketball there, I can’t help thinking of my school years.
A. view B. sign C. sense D. Scene
There are so many viruses on the Internet. If ______ accidentally, the viruses may make your computer break down.
A. downloading B. to be downloaded
C. downloaded D. being downloaded
I _______ to your party, but I was prevented by the heavy rain.
A．had meant to come B．was about coming
C．have meant to come D．meant coming
---Where did you come across your old classmate Jane?
---It was in the supermarket _______ she worked _______ I came across her.
A．where; when B．that; when
C．that; that D．where; that
However, at times this balance in nature is ______, resulting in a number of unforeseen effects.
A. troubled B. disturbed C. confused D. Puzzled
