---Dad must we wait until the light becomes green?---Yes I’m afraid we.That’s the traffic

问题补充：

---Dad, must we wait until the light becomes green?

---Yes,I’m afraid we.That’s the traffic rule.

A. can

B. may

C. have to

D. need

答案：

A. can

B. may

(答案→)C. have to

D. need

解析：爸爸，我们必须等到变成绿灯吗。是的，我们恐怕不得不等到绿灯，这是交通规则。have to 不得不，强调客观原因。故选C。