If you’ re unsure, ask the customer to spell their name. 如果你没有把握，就请顾客把他们的名字拼写出来。

+ofabout Police were unsure of the motive for the killing. 警方不清楚杀人的动机。

+whetherif I was unsure whether to leave. 我拿不准是走还是不走。

+howwhatwhy etc She was unsure how to tell him. 她不知道该如何跟他说。