Prosím Vás, dá se použít not only that takto na začátku věty.

(1) Not only that poor waste management is the major cause of animal deaths, but it also affects humanity in a serious way.

Nebo je gramatická jen tato možnost s inverzí:

(2) Not only is poor waste management the major cause of animal deaths, but it also affects humanity in a serious way.

Swan uvádí větu:

(3) Not only the bathroom was flooded, but also the rest of the house. Zde inverze není, tak nevím, jestli je inverze vždy nutná, pokud je „not only“ na začátku věty. Také už to není daleko k větě číslo (1), kde inverze není a je navíc jen „that“.

Děkuji moc za odpověď.

The problem here is that we're looking at a single sentence in isolation, out of context.

„Not only that …“ at the start of a sentence looks odd, but it could work as the start of a new clause with the appropriate punctuation, e.g. There are many reasons why waste needs to be managed: not only that poor waste management is the major cause of animal deaths, but it also …

Sentence (2) is ok. Sentence (3) is ok with or without the inversion, if the intended meaning is that the bathroom was not the only part of the house that was flooded. In other words, it answers the question „which parts of the house were flooded?“

• Not only the bathroom was flooded, but also the rest of the house.
• Not only was the bathroom flooded, but also the rest of the house.

In a different intended meaning, answering the question „what happened to the bathroom?“, inversion is necessary.

• Not only was the bathroom flooded, it was completely destroyed.
• Not only the bathroom was flooded, it was completely destroyed.