In fact, _______ one cause that leads to the problem.
| A．cattle is | B．cattle are |
| C．cattles are | D．the cattles are |
The professor was so ______, hardly anyone came to class.
| A．popular | B．boring | C．friendly | D．lively |
Jake’s passed his exams. We’re going out to ______.
| A．joke | B．invite | C．celebrate | D．argue |
We couldn’t understand: what could ______ his sudden change of mind?
| A．enjoy | B．explain | C．accept | D．mean |
I didn’t mean to break your vase—it was just ______.
| A．an accident | B．an advantage | C．an agreement | D．an experience |
He was breathing ______ after the relay race.
| A．heavily | B．slowly | C．carefully | D．weakly |