12.You will succeed in the end　　you give up halfway.

解析：此为unless引导的条件状语从句，意为“除非”。句意：你最终会成功，除非你中途放弃。

答案：unless

11.Roses need special care so　　they can live through winter.

解析：此为so that引导的目的状语从句。so that意为“以便……；为了……”，引导的状语从句中常用情态动词。

答案：that

10.　　I like Chinese food，I won't visit that restaurant today.I'd like to try a different one.

解析：此为although引导的让步状语从句。although尽管。句意：尽管我喜欢中国食物，但我今天不会去那家餐馆。我想试个不同的口味。

答案：Although

9.He was talking as　　he knew everything about it.

解析：此为as if/as though引导的方式状语从句。其中as if或as though引导的从句一般用虚拟语气，但如果从句中所陈述的情况很可能实现，也可用陈述语气。句意：他正谈论着，似乎他无所不知。

答案：if/though

8.I won't tell him the correct answer even　　I know it.I don't like him.

解析：此为even though/even if引导的让步状语从句，even though/even if(即使)。句意：我不会告诉他正确的答案，即使我知道答案。我不喜欢他。

答案：if/though

7.He had just finished the book　　supper was served.

解析：when用作并列连词，其意义为“那时，这时”，相当于and at this/that time。句意：他已经完成那本书了，那时晚饭端上来了。

答案：when

6.I was having dinner　　I heard a knock at the door.

解析：when用作并列连词，其意义为“那时，这时”，相当于and at this/that time。句意：我正在吃晚饭，那时我听到敲门声。

答案：when

5.A whole month had passed　　she fully recovered.

解析：此为before引导的时间状语从句，before还未……就……；不到……就……；……才……；趁；还没来得及。句意：一个月过去了，她才完全康复。

答案：before

4.　　you've got such a golden chance，why not make the best of it？

解析：此为since/now that引导的原因状语从句，since＝now that既然。句意：既然你得到一个如此宝贵的机会，为何不充分利用呢？

答案：Since/Now that

3.A new supermarket was built　　there had once been a wasteland.

解析：where引导的地点状语从句。句意：一家新的超市将在那曾是废墟的地方建立。

答案：where