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

—I haven’t seen Tom for years. Any news about him?
—He          in a toy factory for two years. Now he’s working on a farm.

—Time       . It’s likely that we will miss the bus.
—Don’t worry. There are still 10 minutes left.

Up to now, the program ______ thousands of children who would otherwise have died.

It took me a long time before I was able to fully appreciate what they ______ for me.

---I’m sorry, but I don’t quite follow you. Did you say you wanted to return on September 20?
---Sorry, I ______ myself clear. We want to return on October 20.

I       the office yesterday afternoon when a stranger came in with a boy．

--- Tony, you must have noticed the student who broke the glass．
--- I’m sorry．I           attentively．

I’ve got two tickets for tonight’s concert. I ___________ my little sister.

He doesn’t know the city very well, because this is the first time he _______ here.