It ______ last week that the haze (雾霾)in Beijing caused many problems.
举一反三
- Lack of ________ of environment protection has caused many problems.
- The increasing demand of cars has caused many problems.
- Many accidents ______ by careless drivers last year. A: are caused B: were caused C: was caused D: caused
- Last week two engineers ______ to help solve the technical problems of the project.
- Many accidents____ by careless drivers last year. A: are caused B: were caused C: have caused D: will cause