Some English scientists are identifying problems ____ technology in the 21st century. If solved, the solutions could change the world.
#97172
A
facing
B
faced
C
being faced
D
having faced
推荐题目
They suggested that the professor _____ just now _____ chairman of the meeting.
#90757
A
referring to; was made
B
referring to; be made
C
referred to; be made
D
referred to; was made
You can’t imagine what difficulty we had_______ home in the snowstorm.
#92314
A
walking
B
walk
C
to walk
D
walked
_ properly, a car can be used for many years.
#90465
A
Maintained
B
Maintaining
C
To be maintained
D
To maintain
_______ in the queue for half an hour, Tom suddenly realized that he had left his wallet at home.
#93916
A
To wait
B
Have waited
C
Having waited
D
To have waited