Subject + 在 + 旅行 + 中
The verb 旅行 (lǚxíng) means 'to travel' or 'to take a trip.' It refers to journeying to different places for pleasure, exploration, or other purposes. It can also be used as a noun meaning 'a trip' or 'travel,' as in 旅行中 (during the trip).
我打算暑假去日本旅行。
Wǒ dǎsuàn shǔjià qù Rìběn lǚxíng.
I'm planning to travel to Japan during summer vacation.
他们夫妻俩喜欢一起旅行。
Tāmen fūqī liǎ xǐhuan yìqǐ lǚxíng.
The couple enjoys traveling together.
旅行中我认识了很多有趣的人。
Lǚxíng zhōng wǒ rènshi le hěn duō yǒuqù de rén.
I met many interesting people during my travels.