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
