This problem is very difficult.

The difficulty of this problem makes me scratch my head.

He believes in Darwin's theory of evolution.

His theory is very interesting.

Surumeika is a type of squid that is often seen in the seas of Japan.

He is from a distinguished family in Japan.

In this museum, masterpieces from around the world are on display.

His guitar is truly a masterpiece.

Please specify all the contents of the contract.

He was appointed as the president.