历史上,贝壳、粮食、皮革都曾充当过商品交换的媒介,但伴随着商品交换的发展,“贵金属”长期占有了货币的宝座。这是由于“贵金属” ①化学性质稳定、便于保存、携带② 可用作装饰品 ③具有很高的价值④ 质地均匀、便于分割
Our teachers don't allow us ______ mobile phones in the school.
to use
use
using
- How clean the roads are!
- They ______ by the hard﹣working cleaners every day.
are cleaned
clean
will clean
- Jack,how do you like the new movie Hi,Mom!directed(导演) by Jia Ling?
- Well,it's really a funny movie.I ______ it for three times.
am watching
will watch
have watched
My father always tells me never to ______ when I am in trouble.
give up
put on
help out
- Hey,Clark.Would you like to have a picnic with us this weekend?
- Sorry,I'll have an exam next Monday,so I ______ prepare for it.
can
may
must