a sequence of什么用法?sat08年真题上的

问题描述:

a sequence of什么用法?sat08年真题上的
A sequence of training sessions on the use of the new equipment is scheduled for this coming tuesday at the technology、
就是中间的那个IS 划线 那个IS就是对的,为啥?

a sequence of 一系列
A sequence of training sessions on the use of the newequipmen作主语,单数