20．-Why do you look so upset?

　　　 -There are so many troublesome problems ____________．

　　　 A．remaining to settle 　　　　　　　　　　　　　　　 B．remained settled

　　　 C．remaining to be settled　　　　　　　　　　　　　 D．remained to be settled

19．The driver managed not to hit the child who ran in front of his car, but only ____ injuring himself．

　　　 A．in hopes of 　　　　 　　　　　　　　　　　　　　　　 B．as a consequence of

　　　 C．at the mercy of 　 　　　　　　　　　　　　　　　　 D．at the cost of