□ 시간과 조건 부사절에서 접속사 뒤에 주어+동사를 생략하고 분사가 올 수 있다.
while, when, before, after, and since -ing
eg. 1. When waiting for a bus, they are reading a book.
= When they are waiting for a bus, they are reading a book.
2. I'll practice smiling while looking in the mirror.
= I'll practice smiling while I am looking in the mirror.
3. Take the medicine before going to bed.
=Take the medicine before you go to bed
4. Be careful when (you are) walking down the street.
= Be careful walking down the street.
※ A preposition phrase with before, after, when, while or since
<Adverbial Clauses>
In traditional grammar while, when, before, after, an since are conjunctions which join an adverb clause to an independent clause. The term adverbial clause is used because the clause adds time-related information about the verb and answers the question When? This added-on structure is called a dependent clause because it can not stand alone as a sentence.
Temporal Location Expressions
In current linguistic analysis— while, when, before, after, and since —have been re-classified into the category of preposition. Each of these temporal expressions takes a finite clause or nonfinite clause as its complement.
Preposition (PP) + finite clause : 정형
- John saw a skunk while he was walking home.
Preposition (PP) + nonfinite clause : 인칭
-John saw a skunk while walking home.