—Oh, my God! We have missed the last bus. What shall we do?—I’m afraid we have no ______ but to take a taxi.

These natural disasters have warned us that everyone should start to protect the _____ immediately.

 ---Mom , my shoes are all ______ . ---Oh , you need some big ones . Let’s go to the store this afternoon . 

Many countries are using natural gas , wind and other forms of ________ .

 –What does the ________ mean? --It is a place to live in space.