基本信息
21．With the development of modern technology, plane, in most cases, becomes most popular means of transptation.
A．a; theB．the; aC．the; theD．a; a
22．--- I have been great pressure at wk lately.
--- I am your service if necessary.
A．under; fB．in; atC．under; atD．in; to
23． to some social activities, Mary is always finding some unimptant excuses to refuse.
A．When being invitedB．When inviting
C．When invitedD．When to be invited
