1 . Yuan Longping devoted his life to the research and development of high－yielding rice, making outstanding contributions to China’s food ________.

A．lack

B．cuisine

C．security

D．purchase

2 . The selection process in the job market is based on standard tests of ________ and experience.

A．concept

B．crew

C．competence

D．cruelty

3 . Some regional and international passenger flights remain ________ until further notice due to the rising concerns over the virus.

A．crashed

B．conducted

C．suspended

D．sustained

4 . Popular band Westlife held their first virtual concert on Friday night, which was ________ on WeChat and attracted more than 20 million Chinese fans.

A．claimed

B．attached

C．captured

D．streamed