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同学好，
alternative
An alternative plan or method is one that you can use if you do not want to use another one.
（计划或方法）可替代的；可供选择的
The opposition parties have so far failed to set out an alternative strategy.
反对党到目前为止还没有提出其他的策略。
An alternative venue for the concert is being sought.
正在寻找其他可举办音乐会的地方。

https://dictionary.cambridge.org/dictionary/english-chinese-simplified/alternative

nuclear power意思是核能。

(also nuclear energy)
the power produced when the nucleus (= central part) of an atom is divided or joined to another nucleus:
The expansion of nuclear power is a politically charged issue.
The substance is a byproduct of the processing of uranium for nuclear power.

https://dictionary.cambridge.org/dictionary/english/nuclear-power

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