You ______ wear sports shoes when you climb a mountain.
We don’t have enough nurses to look after the patients. At least _____ are needed.
— Hello, may I speak to Sandy?— .
Miss Gao isn’t here. She _____ to the bus station to meet Mr. Brown.
If you do things ________, usually you can’t do them well.
— Do you know ______ the MP4 yesterday?— Sorry, I’ve no idea about it.