Sarcasm is verbal irony used in a mocking way, I believe.
Answer:
Astronauts on the International Space Station <u><em>have </em></u>a busy schedule. Every day they <u><em>wake up</em></u> at 7:00 GMT. From 7:00 to 8:00, they wash up and <u><em>eat </em></u>breakfast. At 8:00 in the morning, they <u><em>call </em></u>Ground Control in their countries. After they talk to Ground Control, their workday begins. The astronauts <u><em>don't do</em></u> the same thing every day. Their schedules change every week. The astronauts do not work all the time. Each day they <u><em>exercise </em></u>for an hour in the morning and an hour in the afternoon. After dinner, they <em>have </em>free time. Then, it <u><em>is </em></u>time to go to sleep. Sometimes this <u><em>isn't </em></u>easy because the sun rises and sets 16 times each day on the space station!
Explanation:
All the verbs in the text are written in the Present Simple tense, since the paragraph refers to actions that are either facts or happen regularly at the International Space Station. Thus, the astronauts at the station have a program of daily routine actitivies.
