在英语中，“我用手想了想”可以用以下几种方式表示：
I thought it over in my mind/head.
我在脑子里仔细想了想。
I took a moment to consider it.
我花了一点时间考虑一下。
I weighed the pros and cons.
我权衡利弊。
I reflected on it.
我仔细思考了一下。
这些表达都表示在思考某事物或问题时花费时间思考。
例句：
I thought it over in my mind and decided to go back to school.
我在脑子里仔细想了想，决定重新上学。
I took a moment to consider it, and then I decpned the job offer.
我花了一点时间考虑一下，然后拒绝了工作机会。
I weighed the pros and cons, and in the end, I chose to invest in the company.
我权衡利弊，最后决定投资这家公司。
I reflected on it for a while, and then I reapzed that I was wrong.
我仔细思考了一下，然后我意识到我错了。