单选题 (When each time) he (came) to Beijing (on business), he (would) call on me.
【正确答案】 A
【答案解析】连词用法错误，应改为Each time。each time...“每次…”，这个名词短语本身可以起连词的作用，可以引导时间状语从句。类似的还有the moment...。