55.3
问题描述：
55.3
do you know that our monitor,along with some other classmates,____our maths teacher in hospital already
a.have visited
b.will visit
c.has visited
d.had visited
答
C对,
句子的主语是our monitor.
along with some other classmates是伴随状语.根据主谓一致的原则和句子中的时间状语already可以确定答案是C.