谁能帮我解释下这个为什么选C阿I just don't understand (. )that prevents so manyI just don't understand (. )that prevents so many Americans from being as happy as one might expect. A.why it does B.what it does C.what it is D.why it is.

帮我解释下为什么选这个答案 谁能帮我解释下这个 谁能帮我解释下这个为什么选C阿I just don't understand (. )that prevents so manyI just don't understand (. )that prevents so many Americans from being as happy as one might expect. A.why it does B.what it does C.what it is D.why it is. 要解释下为什么选这个答案 解释下为什么选这个答案 谁能帮我解释下这个图 谁能帮我解释下这个电路.怎么求电流输出I? I had hoped that John ______a year in Africa,but he stayed there only for three months.A.spends B.spent C.would spend D.will spend 为什么选C 谁能帮我解释下 帮我解释下这个式子!为什么等于M When my mother came back home last night,I was still _________.A.wake B.woke C.waking D.awake我知道选D,能解释下为什么不能选C么?i was waking和i was awake区别 Mr Wang told some stories too make us_.A.laugh B.laughed C.laughing D.to laugh能不能帮我解释下为什么选这个选项。 帮我解释下为什么选D 谁能帮我解释下这个内涵图,为什么看不懂,下面第二个是什么东西 条件概率,懂得进为什么P(A I B)= P(A n B)/P(B) 谁能帮我解释下这个公式?再给予B的情况下求A...然后就AB交集的概率除以B?为什么 谁能帮我解释下这个电路.怎么求电流输出I?这个图中电路怎么分析,电流I怎么计算 I have to turn off the light.为什么要加the~有时我这个分不清～不知道是加the 还是a谁能具体给解释下~ 谁能帮我解释下这个开关的工作原理? 谁能帮我解释下这个字的含义聿,