单项选择题
Go and()when the train is leaving.
A.be sureB.make sureC.be sure ofD.be sure that
单项选择题 Our motherland didn’t always look the way it()today.There were few tall buildings.
单项选择题 By the time he realizes he()into a trap, it'll be too late for him to do anything about it.
单项选择题 Make sure you've got the passports and tickets and()before you leave.