Professor Peter和他的四个学生，后面用are没错啊，为什么用is呢？

Question

Professor Peter, with four of his students, are attending a symposium in Nanjing on energy.
A B C D
B, are----is

Answer 1

改成这样你就明白了：
Professor Peter is attending a symposium in Nanjing on energy, with four of his students.

这是主谓一致经常考的题目。
主语是Professor Peter
with four of his students可以看成定语
谓语就是单数了。
类似：
The boss with four boys is coming tonight.

Answer 2

看清楚，主语只有Professor Peter， 那4个学生前面有个with。