Information as follows, but it would help to have the entire sentence or paragraph.

There is nothing wrong with the way you said it, There are many ways to convey this meaning, you could say " I need to keep on top of new developments in my field." or "I need to stay up on the latest research"

1 I have yet to receive such warnings. （You have not been informed by anyone about problems/ dangers/ illegal issues with whatever they are talking about.) 2 He was being pulled out of his house. (He was physically being removed from his house, pulled out) Why the author use "refuse to" not " are refusing to " in the sentence below ? If you refuse to turn in the gun, you could be charged with a felony. (either is fine grammatically, "are refusing" is occurring right now, "if you refuse" could mean a less definite time, maybe tonight, tomorrow, etc.

我觉得你的意思是， “airing out the blankets", "hanging the blankets outside to air out"

Your sentence was good, better than your second attempt. I would say "What is a reasonable percentage of design cost to total cost? " or "What is the reasonable percentage of design cost in the total cost?" But your sentence was fine.

This is a little confusing to me, "I noticed that my nephew was happier when his mom gave him 3 candies rather than 2 like last time, even though the second time he actually got a smaller percentage of the total number of candies." OK he liked 3 candies more than 2 and last time he was given 2 candies, we don't know when he was given 3, I don't know when the second time is, is the 3 candies just now or earlier than the 2 candies. So the you add " This time his mom gives him 3 candies, ( so now I know this time is the 3 candies) the total number of candies might be 15. Last time his mom gave him 2 candies. The total number of candies last time might be 8. (so this time, the second time, he got 3 different candy types with a total of 15 candies) (So your next statement is not correct, this time he got more candy types and more total candy)( So I am confused, it may have to do with Chinese and English issues with before and after, first and second) So this time, my nephew actually gets smaller percentage of allocation. How to convey this message?

These are two different people speaking, the first person asks what is happening with his bid (proposal, offer to do work for money). The second person responds that he still has the bid with him, (it is still with me) and that he has to review it. "Are you still with me" can be mental or physical. Your teacher wants to know if your mind is still with her mind, if you understand. It could also be used to ask if someone is physically still going with you or accompanying you.

One phrase I think is missing one word, it should be "to have an ace up the sleeve" These phrases are all common sayings to me and well understood but then I am 60 years old. I wouldn't say they are used extremely often but I believe most people understand them.