游客携带中药材、中成药出境,前往国外的,总值限人民币300元。()
A.正确
B.错误
参考答案:对
Students are asked to _____ themselves in this boarding school and they are only allowed to go back home once a week.
A.act
B.behave
C.perform
D.observe
带传动是依靠传动带与带轮之间的()来传动的。
A.作用力
B.张紧力
C.摩擦力
D.弹力