They ______ go out for dinner, but not very often.
On this day,Dr.Martin Luther King_______,but we didn't know who________him.
Mary likes helping others._______, she often helps the old cross the road after school every day.
I didn't understand_______. So I put up my hand to ask.
—Where were you doing when I called at your house this morning?—Oh,I______ for a friend from New York at the airport.
David is always so busy____he has little time for his family.