为什么C错了!T^T

为什么C错了!T^T 求概率论大神教这题T^T万分感谢 A知道为什么错了 不知道为什么选C 【概率论】 A知道为什么错了 不知道为什么选C 求大神教呀T^T 80、He must have left home yesterday,he?A．hasn’t B．didn’t C．mustn’t D．needn’t选了A为什么错了? 83、You need to come earlier,you?A．don’t you B．needn’t C．don’t D．won’t选B为什么错了? 高数积分基础问题为什么等于f(t)+c了,不应该是f[g(x)]+c么φ（t）不是g(t) 错了那两道题谁会?T^T -I'm sorry,but i don't quite follow you.Did you say you wanted to return on September 20?-Sorry,I_myself clear ,We want to return on October 20.A.hadn't made B.wouldn't make C.don't make D.haven't made正确答案是D为什么不选C呢,C错哪了 -Can I help you,sir?-Yes,I bought this radio here yesterday,but it_______.A didn't work B won't word C can't work D doesn't work为什么不能选b说错了，为什么不选c 为什么拉用t,压用c,工程力学 C语言的一道交换的 ｛t=x%y;x=y;y=t} return x; 为什么x的值等于t了 He must have done his homework last night,didn't he? 这里为什么用didn't而不用haven't?错了 是 hasn't ---- Your phone number again?I ___ quite catch it.---- It's 69568442.A.didn't B.couldn't C.don't D.can't正确答案是A为什么不选 BCD?请说明不要在那berber为什么选A对 我要的是为什么B C D 错了没有听明白么？我说的是 I can’t hear what这句为什么错了? 请问∫sec t dt为什么等于ln |sec t+ tan t|+C? Would you mind doing the dishes?A certainly.B sorry,I won't.C Ok,I'll doing them in a minute.D Piease don't.答案是C为什么,请说明原因,please 打错了 C应该是do If he_____free,he'll call me.A.does't B.isn't C.won't D.don't为什么用Isn't而不用Won't Let's park our car here.A don't B needn't C mustn't Dwon't 为什么呢?