I have two questions.
1:"Someone is at the door. Go and ( ) who it is."
a:search
b:look
c:find
d:guess
e:get
I was given five alternative to fill in the blank with, and the correct one is "look". Is it an ideom and should I remenber it off by heart? The reason why I care this sentece is "look" usually accompany a prepositon when it has object, so "find" looks more rational for this sentece. Maybe, it's not though. Can anyone explain what I am wondering?

2:"The price of books is getting ( ) these days"
a:cheaper
b:higher
c:more affordable
d:more expensive
Which is correct and why the others are not suitable?Thank you for your help!As for the second one, my text book say b is correct, so I want to know how to chose b.

Question

I have two questions.
1:"Someone is at the door. Go and (   ) who it is."
a:search
b:look
c:find
d:guess
e:get
I was given five alternative to fill in the blank with, and the correct one is "look". Is it an ideom and should I remenber it off by heart? The reason why I care this sentece is "look" usually accompany a prepositon when it has object, so "find" looks more rational for this sentece. Maybe, it's not though. Can anyone explain what I am wondering?

2:"The price of books is getting (     )  these days"
a:cheaper
b:higher
c:more affordable
d:more expensive
Which is correct and why the others are not suitable?Thank you for your help!As for the second one, my text book say b is correct, so I want to know how to chose b.

Answer

To answer your question honestly, I would memorize it by heart, because many english speakers do use "Look" in that particular sentence. And for the word "Find", I would add the word " Out" after it. That makes sense too. "Someone is at the door. Go and find out who it is."

And for the second sentence, all of the answers are acceptable, but you can change the question a bit too, but the one that you've used is fine as well. Another way to reword the sentence can be "The prices of books are getting () these days." Both are fine.