Dear teachers,
I have four questions to ask:
No.1
I've picked out/ up a Chinese novel to give to my nephew as a gift.
I get confused why both "pick out" and "pick up" are correct?
I know "pick up " means "buy". But "pick out" doesn't have such meaning. could you please explain why "pick out" is correct here? "
to Pick out" means "to choose", "I've chosen a Chinese novel to
No.2
We should put our differences
away and work together for your common goal.
My question is: can I use "aside" instead of "away"?
Yes you can.
No.3
If we persist with our effort, we will succeed in our financial reform.
I know I can say "persist in doing something". Is "persist with something" a phrase?
Yes it is.
No.4
I think "think about" and "think of " are of the same meaning. So are they interchangeable in the following two sentences:
Let's go skating and stop thinking about all these problems.
The job pays well, but I'm thinking of giving it up.
Yes they are. 
Looking forward to hearing from you.
Thank you in advance.
Jiang