BACKER x SPONSOR x FUNDER: what's the difference? (real life examples) business venture what is it?

DIFFERENCE: "all the times" vs "every single time" / "in a higher degree others less" meaning? I've been through these situations and it hurt me _______ (a) , some in higher degree others (b) a) all the times VS every single time b) lower VS less context: someone is having a difficult time and I've been through those types of situations, in the past, it hurt me ______ (I meant to say every time the situation happened it would hurt me) and that kind of pain would depend on the situation, so in some situations it would hurt more and in others it would hurt less. that's why the "higher degree", so I wanted to say "some in a higher degree and others in _____" I don't know if I put "lower degree" or substitute for "less". Does that make sense?

"there is many..." "quotas are racist" plural or singular? I saw both phrases being used by native english speakers so I got confused... the correct is "there are many..." and "racial quotas are racists" right? because "many" means more than one and "quotas" are plural.

"Have you went to the U.S.?" is correct? What's the difference between that phrase and "have you been to the U.S.?"

what is a PROMPT? (card prompt, discussion prompt) I've searched on the dictionary but couldn't understand either way. Below, I will share some examples that showed up to me, in different situations: 1) CARD PROMPT I downloaded an app to learn new vocabulary and there's a game to practice my knowledge. In one of the options there's this: settings ''a- question format: written, matching,multiple choice ; b- front or back: ( ) FRONT OF CARD IS THE PROMPT ( ) BACK OF CARD IS THE PROMPT'' 2) DISCUSSION PROMPT (found this on an online course) a- introduction video b- course goals and weekly learning objectives c- information about regions d- practice quiz e- Discussion prompt ''Discussion prompt: set your goals and be successful. Before you get started, share with your fellow learners a little bit about who you are, why you are taking this course and how you are planning to make sure that you finish the course successfully. We can't wait to meet you.'' What does prompt mean in this TWO examples? Can someome explain to me?

''If you have any doubts or questions, let me know'' Is it correct? Does it sound natural? I was watching a video and the teacher said ''any doubts or questions, just leave your comments below''. I see that many native speakers don't use 'doubt' in this context like ''I have a doubt'' (they use ''I have a question'') because ''doubt'' seems like you are suspicious that something is not right, taking off the credit of the person; and that is not the intention. But here, the English teacher used ''doubt'' so I wanted to know if he used it wrong. And if not, what word can be used to replace ''doubt'' ? (meaning: I don't know if I use X or Y in the formula - not really asking a question but stating ''I don't know when to use each one'', then the teacher will explain when to use X and Y, not directely asking to the teacher)

can I say "pay there a visit" or "pay a visit to the country" ? Oh, you live there? I think that country is a beautiful place, if I have an opportunity I will ___________ I want to replace with - pay there a visit. - pay a visit to the country. I don't wanna say "pay you a visit" because it means I want to visit the person. I want to say "visit the country" but I want to use "PAY .... a visit ..." because it sounds more nice. I wonder if it is possible to replace the person for "there" or "city/country"...

what's the difference between 加强，改進 and 提高？[TO IMPROVE] can you give me examples? example: I want to improve my pronunciation and writing skills the most. How do I say "improve" and "the most" in Chinese? which word do I use? And please could you give me examples of 改進 and 提高 too? 谢谢。

''SURNAME'' and ''LAST NAME'' are not the same? Please consider my examples below to answer. I've been taught that ''surname'' is the ''2nd name'' and the ''last name'' is the last of all, but I've seen people saying that surname and last name are the same so I got confused. according to what I was taught: example 1) Rafaela Camargo Pereira Correia surname= Camargo last name: Correia example 2) Ana Liu Chen Mei surname: Liu last name: Mei People say that in the U.S. people use ''LAST NAME'', and it is the FATHER'S ''NAME''. But in the 2nd example, Liu came from her father but it's her SURNAME. (in Chinese the ''surname'' - from the father - comes first) So if they are used in as the same meaning, which one should I use? I'm going to create an account on LinkedIN and I wanted to use only 1 ''last name/surname'', so which one do I pick? Is it okay to not use my father's? I'm very confused, native English speakers, which one do you often use?