我每天有如此多的工作以至于我经常熬夜.
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Jack enjoys and sunbathing with his friends. (游泳)
There are many online libraries where you can read books for ________, such as the national Online libraries Library of China and Shanghai Library. (免费的)
The app about how to learn Chinese is very popular ________ the foreigners.(在……当中)
Jumping the rope is a kind of full-body exercise and it is great for the ________(大脑).
No country is safe ________ all countries are safe. (除非)