【注音】：qián kǒu 书籍出版术语。前口也称口子或口子边、书口。指书刊的翻阅口，即订口的相对面。
纤毛虫最重要的3个类群为下毛目、肾形目和前口目，其中又以下毛目种类最丰富。
The 3 most important groups of soil ciliates were Hypotrichida, Colpodida and Prostomatida, among which Hypotrichida had the greatest richness of species.
爸爸把碗柜放在马车的座位下面，又在柜子前放了满满一口袋的谷子作为马的食物。
Father put the cupboard under the wagon-seat, and in front of it and he laid a sack of corn for the horses.
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