Sorry,I can't follow you.Please say it again.當中的I can't foll

題目：

Sorry,I can't follow you.Please say it again.當中的I can't follow you 用I don't understand.還是用
I can't catch up with you .用哪個好.

解答：

用I can't catch up with you比較好,因爲前面的句子是I can't follow you,句子是表達我不能跟上你,請再說一遍,而catch up with這個短語也就是跟上,趕上的意思,而 don't understand是不能理解的意思,跟句子的意思不符