问题
选择题
How to control housing price is said to a great challenge facing the government over the past few years.
A．become
B．becoming
C．have become
D．be becoming
答案
答案：C
本题考查非谓语动词。题中考查不定式的时态，根据语境：已经成为一个巨大的挑战。故用不定式的完成时。选C。