In fact he knows this place very well, for he ________ there three times.

We usually go to school on weekdays, and sometimes go to cinema at weekends.

Do you know _______ the girl in red is?—I’m not sure. Maybe a doctor.

Hefei is a beautiful city, isn’t it?—Yes. There are about two ____ visitors here week.

We were swimming in the lake _____ suddenly the storm started.