For him, it never took long to put an idea into action. 請問一般寫作可以這樣寫嗎?

It's indeed a correct and powerful statement.

For這個字,在

1. For him, it never took long to put an idea into action.
2. For the welfare of the people, the ... to these social problems.

這2句話裡面的意思 是不一樣的.(2)裡面,For 是表示目地.
盡管如此,你新的改寫 也是可以的.
不過 你的2個改寫 應該是互不關聯的.

> 更新 2: @prisoner26535 如果...
除了句尾的句點的缺失以外,你的改寫是可以的.

As to him, it never took long to put an idea into action. Yip

ㄨ

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The idiomatic expression using "take" to relate to "time" should be:
1. take somebody something (to do something)
e.g. It took him a long time to put an idea into action.
2. take something for somebody to do something
e.g It took a long time for him to put an idea into action.

For negative sentences, we can use the adverb "long" to replace the time expression "(for) a long time".
~ It did not take long for him to put an idea into action.

We can use "never" to emphasize a negative statement instead of ‘not’.
~ It never took long for him to put an idea into action.
= It never took him long to put an idea into action.

We can also put the preposition phrase in front, at the beginning of the sentence for emphasis.
~ For him, it never took long to put an idea into action.

"For (the sake of) the welfare of the people" is a adverbial phrase modifying the main verb "pay" to express purpose. As a typical property of adverbs of purpose, the adverbial prepositional phrase is normally placed at the end but can also be placed at the beginning of the sentence (with comma).