我认为这串钥匙一定是保罗(Paul) 的.
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Our head teacher always (鼓励) us to solve problems by ourselves.
There is a train in now. If you run, you'll just (赶上) it.
The job was so (枯燥) that the young man finally left.
Whoever breaks the law will be (惩罚).
(青少年) are supposed to help with housework to develop their independence.