Hot answers tagged word-choice
顾客 can be explained as "a guest(客) who visits(顾) our shop," that is, a customer. Its opposite site is a retailer. 客户 (client) often refers to one or more people who comes to negotiate a business. Its opposite site is a company or a self employed person (e.g. a psychiatrist or a lawyer). I believe both words appear under Western influence.
The other answer mostly covered it, but I'd like to offer some additional comments. Firstly, note that 应该 can be used to indicate obligation. For instance: 你应该每晚刷牙 (You should brush your teeth every night.) At least to me, there is a certain ambiguity to "should": depending on the context, the emphasis may be more on what is likely (e.g. to use your ...
Generally, you can use 应该. However, as Stan says in comments, it does carry the connotation that there is some reason why it "should" be. So, for example, you could say a sentence like: [要是他六点离开了，]他应该七点到。 [If he has left at six, ] he should be here at seven. If you're just throwing out an estimate, it would be better to use an "I think..." construction. ...
Don't forget 没问题 No problem 可以撒 sure 走起 sure, let's go :D
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