How ______ universe came into being is a puzzle to ______ scientists of all generations. A. the; 不填 B. an; the C. a; 不填 C. 不填;the
This book is well worth _______. Would you like to buy one?
I have bought two ball pens , _______ writes well.
------Why do you turn back? ------ Oh, the bridge ahead_______.
People in the west make_______ a rule to buy Christmas presents for their relatives and friends.
I remember everything ______it had happened yesterday.