______指的是学生对语言知识(语音、词汇、语法、功能和话题五方面)的内容掌握及语言技能(听、说、读、写)的综合运用。

A. for about 40 years
B. for about 27 years
C. since they got married
D. since the writer’s family moved away

A. weak heart
B. taking a shore job
C. failure to return to sea
D. injury caused by a torpedo