Dave's ESL Cafe's Student Discussion Forums

[b7lake]

#1-(1)I kept the door opened.
(2)I kept the door open.
Could you tell me which sentence is correct?

#2-A simple warm-up raises body temperature; the body needs to be
at a particular temperature for certain metabolic reactions to occur
and warming up enables "this" to happen sooner.
I think that "this" indicates "metabolic reactions."
Why is "this" used instead of "these"?

Thanks a lot for your help.

[pugachevV]

I kept the door open, is usual.

Because this refers to the body's need to be
at a particular temperature...

It is only one thing that is necessary and so you can say this.