Scientist are not sure about the ___________ of water on the Mars.
In all his life, Dickens wrote a large number of excellent novels in the 19th century, _____ some are still popular nowadays.
—Tom, your foreign teacher speaks Chinese fluently!—Oh, she has lived in China for six years, otherwise she _______ such good Chinese.
To ensure that children from poor areas can receive fair education, the government has planned to _______ more money to improve the miserable conditions of local schools.
If you absolutely want to get the truth of Malaysia Airlines MH370, _______ wait until the timing is right.
The deal, _______ next week, will allow Charney to make a great fortune in the stock market.