1, the emphasis sentence pattern of the declarative sentence: It is/ was+ the emphasized part (usually subject, object or adverbial) +that/ who (emphasizing the subject, when the subject refers to the person)+other parts.

It was yesterday that he met Li Ping.

2. The emphasis sentence pattern of general interrogative sentences: same as above, just putting is/ was in front.

Did he meet Li Ping yesterday?

3. Emphasis sentence pattern of special interrogative sentences: the emphasized part (usually interrogative pronouns or interrogative adverbs) +is/was+it+that/who+ other parts?

Example:? When and where were you born?

Extended data:

1, which in itself constitutes an emphatic sentence, has no meaning.

Generally speaking, conjunctions only use that and who in stressed sentences, even adverbials that emphasize time and place. That and who can't be omitted.

There are only two tenses in the stressed sentences, the simple present tense and the simple past tense. The predicate verbs in the original sentence are the simple past tense, the past perfect tense and the past continuous tense, the one wIth It is …, and the other tenses with it are …