Professor Brown, together with his students,( ) to attend an i

Professor Brown, together with his students,( ) to attend an international meetingg in Pairs next month.
A、have been
B、are
C、has been
D、is
【正确答案】：D
【题目解析】：be to do 计划做某事，考核together with 短语是连词短语，句子是用单数，主语是professor。