为何不能用where：·······in a secret place where I couldn’ t find it.为何要用that？

为何不能用where：·······in a secret place where I couldn’ t find it.为何要用that？ 为何洗涤硫酸钡不能用氯化钡或硝酸钡同学问我 我不会····没面子啊 where does Mr.Black live?Sorry,I don't know where he lives为何不能用lives in 为何不能用Nacl溶液除去CO2中混有的Hcl?记得二氧化锰与浓盐酸反应生成氯气就是用Nacl除杂的呀·· in which此处为何不可用where代替?The ladder on which I was standing began to slip.为何不能用where来替代 it's keep in the living room. that's where we have it. 为何不能用hold 急··直角三角形能不能用aas证明全等? 作文题目能不能用这个标点符号?就这个标点符号能不能用?爱·美好中间的小点能不能用? The leader of the party was examining the soil near the entrance to the cave.为什么用to?不能用of或者in么?··· they live in shanghai对shanghai画线提问不对的说，where do they 中间还一个空空，然后捏，where do 也不对···· where 和that的用法We live in a consumer society ___there is an enormous demand for commercial products of all kinds.在where 和that中选一个答案是where 为什么不是that呢··求解答 求gre作文电子书2.0版!太傻的不能用了··· 用尺规画圆内接正五边形的方法（不能用量角器量取72·） 造句 一劳永逸,心不在焉,兴高采烈!·造三个句子造点好的，那些都不能用 本杰明·富兰克林为何未能当选总统? Peter Black was born in sydney,Australia.But now he is in Ltaly·····问题：Where is Peter form 为何餐馆不能用英文名? It has been used to detect gold which has been buried in the ground.可以用where么?where 和which可以互换么···有时候觉得where更顺书里用which有时候觉得which更好书上却是where···