If you don't know why, you will give up when it gets tough.

如果不知道为什么，实际行动的时候你可能会放弃。

youdao

At these levels, it gets tough for an investor to make a good return.

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"I thought about all that I've been through and all these memories and sometimes it gets tough, " she said.

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"Well, it gets tough, " White says.

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