The four tones of Chinese, namely ping, shang, qu, and ru, I particularly find the rising tone (jōshō) difficult.

The shipworm is known for eating wood.

We crossed the sea by catamaran.

He engaged in an extravehicular activity from the spaceship.

He is undergoing training for extravehicular activity.

He said, 'See Naples and die,' and went on a trip to Italy.

I was surprised by his shabby clothes.

I came, I saw, and I won.

Himiko is my best friend.

He was gazing at the distant mountains.