When adverbial or adjectival phrases starting with so are placed at the beginning of the sentence for emphatic effect, the subject and auxiliary are inverted:
When an adverb or an adverbial expression of place comes in the initial position (at the beginning of the sentence), the subject and verb are inverted:
In the present simple, the auxiliaries do and does (in the third person singular) followed by the bare infinitive form of the main verb can be used in affirmative sentences to express emphasis. In speech, the auxiliary is stressed:
In the past simple, the auxiliary did followed by the bare infinitive form of the main verb can be used in affirmative sentences to express emphasis. In speech, the auxiliary is stressed:
The to-infinitive is often used in non-finite defining relative clauses after ordinal numbers (the first, the second etc.), superlatives (the best, the most beautiful etc.) and after next, last and only:
