Translating "should" to express what is probable or expected

Question

I've struggled with this for a while, and I haven't found a definitive answer. In English we can use 'should' to indicate an estimation or probability. Merriam-Websters 4th definition is that should

is used in auxiliary function to express what is probable or expected

For example:

He should be here by 7PM.

I should have it done by Friday.

It should run in Windows 95.

I use 应该 but it feels wrong since there is no sense of obligation or demand, whereas there is such a connotation in "should". What should I use?

Answer 1

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. This carries less of a tone of uncertainty than it does in English:

我认为我周五会把这个任务办好。
I think I'll have it done by/on friday.

Answer 2

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 examples: He should be here by 7PM. and It should run in Windows 95.) than on obligation (e.g. I should have it done by Friday.).¹ Thus, only some of your examples of "should" are about "what is probable or expected",

This is also the case with 应该, even when a time-frame (in the future) is specified:

• 他应该七点到---He should be here at 7. This reads as a statement about likelihood to me.

• 你应该星期五之前处理了这件事---You should deal with this matter before Friday. This indicates obligation to me, similar to my first example.

• 我应该星期五之前处理了这件事---I should deal with this matter before Friday. I get the sense that the focus is more on probability, without further context.

When obligation (as opposed to simple expectation) should be "read in" seems to depend on context. For the most part, however, I would be comfortable saying that 应该 can generally work as a translation for "should", at least in the most obvious examples.

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1. The issue of which uses of "should" have which connotations is interesting, but that's an English-language question.

Answer 3

Note that "should" expresses either obligation or expectation. The Chinese term 应该 also expresses either obligation or expectation. For the latter, adding 会 adds to the clarity and adding 吧 at the end of the sentence makes it even clearer.

He should be here by 7PM. If you mean "he is expected to be here by 7 pm": 他应该会在下午7点前到吧。

I should have it done by Friday. If you mean "I must have it done by Friday": 我应该在星期五之前把它做完。If you mean "I expect to have it done by Friday": 我应该会在星期五之前把它做完吧。

It should run in Windows 95. 这（软件）应该能用于 Windows 95 吧。 (Of course a piece of software could not possibly have any obligation to anybody, so there can only by one interpretation)

Thank you.