There are________ products to be sold in the factory store. Which is not correct in the following?
Since nobody gave him any help,he ________ have done the research on his own.(2013·大纲全国,26)
My mom suggests that we ________ eat out for a change this weekend. (2013·陕西,12)
—Why are your eyes so red?You________have slept well last night.—Yeah,I stayed up late writing a report. (2013·四川,5)
I should not have laughed if I________you were serious. (2013·江苏,30)
It ________be the vocabulary that caused you the problem in the exercise because you know a lot of words. (2013·安徽,34)