25. We should help children develop confidence in themselves _____ they can face all the challenges and difficulties with a smile.

A. now that B. even if

C. so that D. in case

26. My brother _____ many beautiful stones over the years and they are of different sizes and shapes.

A. is collecting B. was collecting

C. has collected D. had collected

27. The past ten years have _____ the great changes in all fields of our life, especially in the way we communicate.

A. assumed B. witnessed

C. required D. expressed

28. We invited over 200 guests to our party, but a number of them did not _____ that evening for various reasons, which upset us a lot.

A. stay up B. make up

C. wake up D. show up

29. The doctor is _____ about the girl's illness because he still hasn't found an effective cure for her disease.

A. puzzled B. curious

C. annoyed D. careful

30. Researchers say they have found the _____ in support of their conclusion that our brain activities during sleep are similar to those while we are awake.