about "when"

[alan]

I want to know more about the following sentences' structures about when:

"He bought something when travelling last year."
1.Is the meaning equal to
"He bought something when he travelled last year."

2.moreover,what is the verb form of "when" in the above sentences??
still a conjunction?

3.Is "travelling" a present participle there?

4.I also saw "verb+ed" after "when"...for example
"When confronted with problems,we show our confidence...."
is the original sentence equal to
"When we are confronted with problems,we...." ????

[Casiopea]

Originally Posted by alan

"He bought something when travelling last year."
"He bought something when he travelled last year."

I'd use while travelling.

Originally Posted by alan

what is the verb form of "when" in the above sentences??
still a conjunction?

when he travelled last year functions as an adverbial clause. when is not a verb, so it doesn't have a verbal form. It joins the clause He bought something with the clause he travelled last year, making it a conjunction. If it were something else, say a relative adverb, it would modify the word 'place', like this,

Relative Adverb
He bought something at that place where they have fine wines.

Originally Posted by alan

Is "travelling" a present participle there?

Well, here's a trick to find out: expand the sentence, like this,

While he was travelling, he bought something.

travelling functions as a participle in that context.

Originally Posted by alan

"When confronted with problems, we show our confidence...."
"When we are confronted with problems, we...."

They are the same. 'we are' is omitted because 'we' is redundant. It's stated in the main clause. 'are' is omitted because it goes hand-in-hand with 'we', the subject. If we omit 'we', we have to omit its verb, 'are'.

[alan]

thanks for your help.

In your example,u have changed "when" into "while",
and I understand what your purpose is.

However,in reality,I see "when" is more often used than "while".
such as,

"when paying the charges,u can...."
"when crossing the road,u should..."
"when seeing the signal,u should..."

so are they correct ?

[Casiopea]

Originally Posted by alan

thanks for your help.

In your example, you have changed "when" into "while",
and I understand what your purpose is.

However, in reality, I see "when" is more often used than "while".
such as,

"when paying the charges, you can...."
"when crossing the road, you should..."
"when seeing the signal, you should..."

So are they correct?

Yes. Try looking at it this way, 'while' is synonymous with at the same time as, or as, whereas 'when' is synonymous with at the time/at that time.

EX: He bought something while he was travelling.
EX: He bought something at the same time as he was travelling.

EX: He bought something when he was travelling.
EX: He bought something at the time he was travelling.

EX: When paying the charges (i.e., when the time comes to pay the charges), you can . . . .