1、could you tell me from (where) you borrowed this book?
可以用.where 除了副詞用法外,還可以用作代詞,如：
Where have you come from?你剛從哪里來(lái)?——作介詞 from 的賓語(yǔ)
Where are you going to?你打算上哪兒去?—— 作介詞 to 的 賓語(yǔ)
2、Do you still remember the place (where) we visited last week?
句子中的 place 指的是一塊不確定邊界的地方,如果用 in which,則表示在一個(gè)有確定邊界的處所里面,因此此處只能用關(guān)系副詞 where .
3、it was about 600 years ago (that) the first clock with a face and an hour hand was made.
1）這是一個(gè)強(qiáng)調(diào)句,此處強(qiáng)調(diào)的是時(shí)間狀語(yǔ) about 600 years ago,還原回不強(qiáng)調(diào)句則為：the first clock with a face and an hour hand was made about 600 years ago.
2）強(qiáng)調(diào)句的結(jié)構(gòu)為：it is/was + 強(qiáng)調(diào)部分 + that + 其余部分
4、Who (else) knows he wants to make friends with him?
else 常用于疑問(wèn)代詞 who、what 和 which 或不定代詞之后表示“另外的.../其他的.../ 別的...”,本句話(huà)的意思是“還有誰(shuí)知道他想和他交朋友呢?”.另如：
* What else did she say?她還說(shuō)了些什么?
* Would you like anything else to drink?你還要喝點(diǎn)別的什么嗎?