【单选题】Can you play ________ chess? Please join ________ chess club. [ ]
【简答题】为什么PF 3 既能作为Lewis酸,又能作为Lewis碱?
【单选题】He wants to join the ______ club. He can ______ chess. [ ]
【简答题】A.Chess is a slow . B.Chess must be played across the table. C.Everyone can enjoy chess. D.Chess takes thought.
【单选题】He (is) proud (to have) never been (beaten) at (chess).
【简答题】WWW的中文含义是万维网,英文全称是 。