There a dog and two cats under the tree. A. is B. are C. /

问题补充：

There a dog and two cats under the tree.

A. is B. are C. /

答案：

解析：句意：在树下面有一只狗和两只猫。There be句型用就近原则，主语a dog离谓语最近，因此谓语根据a dog用单数形式is。故选A。