The first textbooks ______ for teaching English as a foreign language came out in the 16th century.
__________ twice a year is the rule that every driver shall obey in this city.
Playing on the football pitch __________.
With the development of the Internet, e-mail has largely __________ the traditional business letter.
I won't buy this iPhone unless the price __________ to under 2,000 yuan.
Since we have made __________,we have to make __________ to achieve more.