is, thirty, ciass, students, are , there, our(连词成句)

问题描述:

is, thirty, ciass, students, are , there, our(连词成句)

there are thirty students in our class.

There are thirty students in our class.
哪个is应该是in,应该是题目出错了把

there are thirty students in our class.
你那个不是is吧,一个句子里怎么可以有两个系动词呢,那样就不是一句话了。