留置直壁不加支撑的开挖深度,对坚硬的粘土不能超过2m,砂土或碎石土不能超过()m。
参考答案:1
It was because of her _____ to children that she gave up a promising career in law to become
a teacher. [ ]
A. devotion
B. concern
C. responsibility
D. mercy
We' ve got to report ( )to the head office.
A. on B. in C. back D. /