是 assessing an overall situation

Question

This is the title of a paragraph in the book "Chinese: A Comprehensive Grammar", by Yip Po-Ching and Don Rimmington, whose content I find really hard to understand. The explanation:

是 shì may also be used loosely to refer to or to make an overall assessment of a situation, rather like its function as a marker of emphasis.

And then some examples:

她是不会来了。
I don't think she will come./She is unlikely to come.
如今是什么办法都试过了
So far we have tried whatever methods we could think of.

I cannot understand what the explanation is supposed to mean. The paragraph before this one explains how to use the "是…的" construction to emphasize, so I also cannot understand the difference between these two patterns, and if the omission of 是 in the example sentences changes the meaning.

Answer 1

她是不会来了。

如今是什么办法都试过了

What your quoted explanation means is 是 is used for an assessment. E.g. 她是不会来了 // the speaker estimates that she wouldn't come. Just like to say judging from current situation, she wouldn't come.

Compared with 是...的, 她是不会来的 is more of emphasis. The speaker is more certain that she wouldn't come. The sentence is saying that it's impossible she would come.

Answer 2

You shall learn how to detect an omitted phrase in a Chinese sentence, and separate a long sentence into meaningful pieces (like clues of a puzzle). For the two cases:

她是不会来了。Actually, the complete sentence should be 我"想(猜,估計)"她是不会来了。 I think (guess, estimate) she won't come.

如今是什么办法都试过了。 = 如今是 什么办法都试过了。如今是 is a customary phrase similar to English - "now the situation is....". There are quite a few phrases that share the same pattern:

• 現今是 = 如今是 = 現下是 = 目前是

• 前題是 Before going further, let's set some things straight. Example: "我願意和你共創事業。 前題是 你必須...."

• 問題是 Before going further, here are some questions/problems, .... "我願意和你共創事業。 前題是 你父母許可嗎? 你有獨立的經濟來源嗎?...."