动因 dòngyīn motive Origin Definitions Defs Strokes Stroke Words Sentences Sents 1 sentence 它们全部由蒸汽机驱动，因此速度慢。 tāmen quánbù yóu zhēngqìjī qūdòng, yīncǐ sùdù màn. They were all powered by steam engines and therefore slow. Source: CCMatrix