21. We won’t give up____ we should fail 10 times.

A. even if   B. since    C. whether     D. until

22. Many questions ____ at the meeting, but the meeting, but he answered none.

A. came up  B. raised   C. were risen   D. asked

23. Her face went red ____ he had said.

A. because that  B. because what  C. because of what  D. because