thefirstthingis[]hellotoourteacherwthefirstthingis[]hellotoourteacherwhenwemeetthemA.said.B.tosay.C.says.D.say

Question

the first thing is [ ] hello to our teacher w
the first thing is [ ] hello to our teacher when we meet them
A.said.B.to say.C.says.D.say

Answer 1

很高兴能够在这里回答你的问题,应该为：
选B
be to do sth 去做某事
当碰见老师时,第一件事是说你好.