1. I'm at a loss for words.我无话可说。
e.g: I’m at a loss for words after hearing such shocking news.
2. .Don't push your luck.别得寸进尺。
e.g: You already got a discount, don’t push your luck by asking for more.
3. I'm having second thoughts.我又犹豫了。
e.g: I’m having second thoughts about proceeding with this plan.
4. I'm a bit overwhelmed.我有点吃不消了。
e.g: I’m a bit overwhelmed with all the work I have today.
5. Let me get back to you on that.我稍后再答复你。
e.g: Let me get back to you on that after I check with my team.