1£®You mustn't go there alone; it's too dangerous.(mustn't/needn't)

2£®It's so near; we shouldn't have taken a taxi.(shouldn't/can't)

3£®You oughtn't to have spent so much time playing computer games.(mustn't/oughtn't to)

4£®—Shall I leave the room so that you two can talk?

—No£¬you needn't.(mustn't/needn't)

5£®He can't have missed the train; he arrived at the train station two hours early.(can't/mustn't)

6£®We'll be very glad if you can join us in going camping.(can/may)

7£®They had to stay in the office last night because of the snowstorm.(have to/must)

8£®We should have helped him; in that case, he would have been able to finish the work.(should/can)