emigrate

immigrate

migrant

答案:migrate

7、 The crime was very cleverly（）.

executing

executive

executed

execution

答案:executed

8、 The difficulty of a problem was ( ) terms of how long it took to complete.

defining in

defined as

defining as

defined in

答案:defined in

9、 Lack of confidence is a psychological（）to success.

barrier

capacity

component

ability

答案:barrier

10、 This dictionary is available in（）form.

electrical

electronic

electric

electronics