One of the rules is that every student ________ wear school uniform while at school.

You _______ call him if you want to, but you _______, for he’ll surely come here soon. 

--Pauline has lost her phone.  –No. It’s in her bag. I _________ hear it.

(2014·济南市名校第四次诊断性测试)—Is the letter from your mother?—Yes.But she ________the letter herself，because she doesn’t even know one word.

 —________ I swim here?—I’m sorry. Children _______ swim alone here.