.20.In the United States,riding bicycles,as an ideal way of

.20.In the United States,riding bicycles,as an ideal way of keeping fit,has become ______ popular.（1分）
A.instantly B.improvingly
C.increasingly D.obviously
.21.The cheerful smile ______ from her face when she heard the bad news.（1分）
A.vanished B.finished
C.accomplished D.established