Mike could not后面接动词原形do，因为could是情态动词，情态动词三大特点（后面接动词原形；可以帮助提问和否定；没有人称和数的变化）之一就是接do。例如：
Could you lend me your dictionary?
你能把字典借我用用吗?
I could do it, he mused.
我能做这件事，他沉思着。
The cheater boasted that he could turn stone into gold.
那个骗子吹嘘道， 他能点石成金
No one could know why he did like that.
没有人知道他这样做的缘故。
