When did you get to the top of the mountain— When we got there, the sun just _________.

When ________ about one of the biggest problems today, many people say that an energy crisis is approaching and is threatening mankind’s survival[ ]

What is your sister going to be ________ she growsup?–She is going to be an engineer.A．before

It is better to travel 10,000 miles to read 10,000 books.

So sudden ________that the residents had no time to escape.