579.With the world changing fast,we have something new ____ with all by ourselves every day.
A.deal
B.dealt
C.to deal
D.dealing
580.We finished the run in less than half the time _______.
A.allowing
B.to allow
C.allowed
D.allows
579.答案是C;用不定式作定语修饰something,表示每天都有新的要处理的事情。
580.答案是C;此处表示被允许，规定的时间。
