這不是時間狀語從句，屬“連詞+分詞”結構。又如：　　

Don’t forget to signal when turning right. 向右轉彎時，不要忘了發(fā)出信號。

You should take your passport with you when changing money. 換錢時你應該帶上護照。

He tends to get carried away when watching wrestling on TV. 他一看電視中的摔跤就很興奮。

They were surprised by her openness when talking about her private life. 她談起私生活時非常坦率，大家都很吃驚。

I have tried to keep your advice in mind when writing the book. 寫這本書時我設法記住你的勸告。　　

When telephoning from abroad, dial 865, not 0865. 從國外打電話，要撥865，不要撥0865。

“連詞+分詞結構”仍屬分詞結構，如Susan was delighted when receiving the roses from her boyfriend一句，其中的 when receiving the roses from her boyfriend 仍為現(xiàn)在分詞短語（只不過是帶有連詞when的現(xiàn)在分詞短語），在句中用作時間狀語。　　

句中的 when 是從屬連詞，不是并列連詞。如 Collins Cobuild 出版的系列語法《英語語法系列——連詞》 (Collins Cobuild—Linging Words) 在第 2.2 節(jié)指出（例句也摘自該書）：　　

有的從屬連詞可以引導縮略從句。這種分句可以是非限定小句：　　

While waiting for the water to boil he made another trip to the bedroom. 等水燒開的時候，他又去了一次寢室。　　

“I had to copy the patterns by hand,” she says, “and had no idea how they would look when finished.” “我不得不用手工仿畫圖案，”她說，“而且對畫好后會是什么樣子心中無數(shù)。”　　

上面雖然沒有“when + 現(xiàn)在分詞”的例句，但它與“while+現(xiàn)在分詞”以及“when+過去分詞”的語法結構是一樣的。