People wondered how such a silly and careless mistakes _______. [ ]

As teenagers, we should _____ seats to anyone in need when taking a bus.—I agree with you.

Too much pressure leads to unhealthy behaviors such as poor eating habits, which______increase the risk of heart disease

t really want to make theappointment, I suppose I ____

No one knows for certain how the first Americans arrived in _____ is now the United States.