Air pollution, together with overpopulation, _______many problems in big cities today.
A: are causing
B: is causing
C: are caused
D: is caused
A: are causing
B: is causing
C: are caused
D: is caused
举一反三
- Shingles ______ by a virus which attacks the nerves. A: is causing B: is caused C: are caused D: are causing
- It rained heavily in the south, ______ serious flooding in many places. A: caused B: to cause C: having caused D: causing
- It rained heavily, ____ severe flooding in the area. A: caused B: causing C: to cause D: and caused
- It is generally believed that the (increase) __________ air pollution has caused serious problems such as global warming.
- The damage()by the flood was so large that the buildings cannot be rebuilt in a short time. A: to be caused B. causing B: caused C: was caused