A professor of biology gave a talk to more than 1000 students on elephants living conditions and the dangers _______ them. 
#102758
A
face
B
facing
C
faced
D
are facing
推荐题目
We________ up by an alarm clock every morning.
#101683
A
wake
B
are waken
C
were waken
D
woke
 Look out! Don’t get close to the building. It _________.
#99785
A
was rebuilt
B
has been rebuilt
C
is being rebuilt
D
had been rebuilt