—Susan, I have a sore throat.—You talked ______ just now. Please drink more water.

---I don’t know how to use this camera.---It doesn’t matter. Here is the___.

-- ________do you usually go to work?--I usually ________a bus to work.

 –How many people were invited to the meeting ?--About six        .

At the top of the high mountains, there is very _____ oxygen in the air.