More bison were killed.The bison population is thought ______ from 60 million to just a few hundred between 1850 and 1910.
The door________open,no matter how hard she pushed.
No one________ be more generous;he has a heart of gold.
—Why are your eyes so red?You________have slept well last night. —Yeah,I stayed up late writing a report.
Harry is feeling uncomfortable.He________too much at the party last night.
—You needn't take an umbrella.It isn't going to rain. —Well, I don't know.It________do.