after that(after与after that的区别)

then是副词，表示然后，于是，接着的意思，例如，You can walk to the bus stop，then ,you can take a bus.After是一个介词,引导时间状语,或者时间状语从句。After that是一个介词短语,也相当于一个时间状语

after 可以作连词用，但是用作从属连词（引导从句），不是并列连词。

你的句子只能填 which，after 在此为介词。若要填 that，则需在 after 前面加上并列连词 and：

(1) You should open an account at the online bank first, after which you can buy anything online. Let's check it out online.

(2) You should open an account at the online bank first, and after that you can buy anything online. Let's check it out online