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.

Understanding the rules of 'Ha-gyou tenko' is difficult.

Before starting his new business, he said, 'A journey of a thousand miles begins with a single step.'