composition

n. /ˌkɑːmpəˈzɪʃn/ B1

成分；构成；作文

The parts or substances that make up something.

仙境例句

The old Tortoise tested the composition of the sea water and found salt, sand and one lost button.

老陆龟检测海水的成分，发现了盐、沙子和一颗丢失的纽扣。