A:a=﹣2
B:a=﹣1
C:a=1
D:a=2
Mary says she will give me a call _______ she arrives in London.
成语加法。
____马平川+____贫如洗=____龙戏珠
____本正经+____管齐下=____思而行
____鸣惊人+____长两短=____面楚歌