I pledged never to break my promise.＝I pledged that I would never break my promise.
決して約束を破らないと誓った
I rather suppose his answer is correct.
どちらかといえば彼の答が正しいと思う
I really must have some air.
少し外の空気を吸わないと
I really need to get to doing my homework.
宿題やらないと
I really think it is interesting; however, some people may not like it.
私は実におもしろいと思うがそう思わない人もいるだろう
I reckon (that) she doesn't know me either.
彼女も私のことを知らないと思う
I repeated that I could not go.
行けないと繰り返した
I shall not expect you till I see you.
当てにしないでお待ちします（ご都合のよいときにお出でください）
I telephoned him that I had no idea.
彼に電話でわからないと伝えた
I think it a pity to waste good food.
おいしい食べ物を残すのは惜しいと思う
