Don’t worry too much about mistakes. They are _ natural part of learning.
—Do you know where David is? I couldn’t find him anywhere. —Well. He _____have gone far—his coat’s still here.
If the new arrangement doesn’t _____, we’ll go back to the old one.
All the girls swam in the lake except two, who _____ halfway.
We’re so busy that no one in the office can _____ for any other work.
You’ll never guess who I met today—my old teacher! We _____ for 20 years.