The black box is a necessary device on an airplane, which records its speed, direction and whether everything on the airplane______ normally. 

---Where is mother? ---She is in the kitchen. She ___ the dinner for the party the whole afternoon.

--How long ___________ each other before they__________ married?--For about a year.

The book ＿＿, it’s a best-seller. 

The school board listened quietly as Jack read the demands that his classmates ______ forward.