He is interested in ichthyological research.

That theory is unscientific and has no evidence at all.

He accidentally held her hand.

I'm troubled by his unproductive attitude.

He was affected by secondary effects.

This is a preliminary plan.

Thinking sensibly, that plan will not succeed.

He is interested in diachronic linguistics studies.

He is interested in synchronic linguistics.

He is thought to be a very unsociable person.