: so that
; in case
; because
标准答案：because
题目58：We are usually very prompt settling your accounts.
: on
; in
; at
标准答案：in
题目59：is very important that you don’t make any mista kes when you calculate those figures.
: It
; That
; What
标准答案：It
题目60：— What if he still doesn't pay up