A penny for your thoughts. 你在想什么呢?
Give it some thought. 多考虑一下吧.
Use your head! 动动你的脑筋! I'll leave you to think. 你自己去思考一下吧.
Let's brainstorm for solutions. 咱们集中脑力来想出解决之方. Everything we speculate has some flaw. 我们的每一样推测都有些缺陷. No point is foolproof. 没哪一项是十全十美的 A:I've decided to resign. 我已决定辞职了.
B:So I gathered. 我也认为你会这么做