哪些从属连词后面可以直接用于过去分词

根据句子意思的需要，有时可以在过去分词前加上一个合适的连词。到底哪些从属连词后面可以直接用于过去分词呢？比较常用的有：

■although

Although exhausted by the climb, he continued his journey. 他虽然爬得很累，但他仍继续前进。

Although never married, they lived together as husband and wife for fifty years. 虽然从未结婚，但他们像夫妻一样在一起生活了50多年。

■as

It usually happens as described above. 情况通常就像上面描述的那样发生了。

Inflation, as measured by the retail price index, is expected to drop. 正如零售物价指数所显示的，预期通胀下降。

■as if

The lad started as if awakened from some dream. 这小伙子一惊，仿佛从梦中惊醒似的。

He was speeding down the motorway as if pursued by a demon. 他在公路上高速行驶，就像有魔鬼在追赶他似的。

■as though / as if

She smiled, as though solaced by the memory. 她笑了，仿佛在往事的回忆中得到了安慰。

■if

If accepted for this post, you will be informed within a week. 如果你被接受担任这个职务，将在一礼拜内给你通知。

The law could arrest the development of good research if applied prematurely. 如果草率施行，该法律将会阻滞高质量研究的进展。

He said they did not want war—but if attacked they would fight to the death. 他说他们不希望有战争——但一旦遭到攻击，定会战斗到底。

Condoms are an effective method of birth control if used with care.  如果使用得当，避孕套是很有效的避孕手段。

■once

Once exposed to light, the film will be damaged and get useless.(= Once exposed to light, the film will be damaged and get useless.) 一旦曝光，胶卷就要被损坏而不能用了。

Once appointed supreme commander, he took the stem measures expected of him. 他一被任命为最高统帅之后，果然就采取了严厉的措施。

■though

I went on talking, though continually interrupted by Dassel. 我继续往下谈，尽管不断被杜塞尔打断。

■unless

The population will grow without limit unless kept in check by starvation. 人口如果不受到饥饿的抑制，将会无节制地增长。

manuscripts cannot be returned unless accompanied by a self-addressed envelope. 除非附有写明自己地址的信封，否则原稿是不能退的。

Unless otherwise specified, all fields have a maximum length of 20 characters. 每个字段的最大长度是20 个字符，除非另作说明。

■until

The virus remains dormant in nerve tissue until activated. 病毒潜伏于神经组织里直到被激活。

Grill for 15 to 20 minutes, turning occasionally until cooked. 烧烤15分钟至20分钟，不时翻转直到烧熟为止。

All the photographs in this book, unless otherwise stated, date from the 1950s. 本书所有照片，除非另有说明，都摄于20 世纪50 年代。

■when

When asked, she confirmed that she was going to retire. 有人问她时，她肯定了她将要退休。

He was reminded of his duty to speak the truth when questioned in court. 他被提醒在回答法庭问题时，有责任讲真话。

The tallest buildings in London are small when compared with the skyscrapers in New York. 同纽约的摩天大楼比较，伦敦的最高建筑物还是算矮的。

■where

The program will prompt you to enter data where required. 这个程序在必要时提醒你输入数据。

■while

While locked up in prison, she wrote her first novel. 在狱中写出了第一部小说。

While flattered I must decline to accept. 虽然我感到高兴，我却不能不婉言谢绝。

The couple took good care of the baby while occupied by their work. 这对夫妇一边工作，一边很好地照顾着婴儿。