16. A peculiarly pointed chin is his most memorable facial ________.

A) mark B) feature C) trace D) appearance

17. John Dewey believed that education should be a preparation for life， that a person learns by doing， and that teaching must ________ the curiosity and creativity of children.

A) seek B) stimulate C) shape D) secure

18. Criticism and self-criticism is necessary ______ it helps us to find and correct our mistakes.

A) by that B) at that C) on that D) in that

19. However， at times this balance in nature is ________， resulting in a number of possibly unforeseen effects.

A) troubled B) disturbed C) confused D) puzzled

20. The patient‘s health failed to such an extent that he was put into ________ care.

A) tense B) rigid C) intensive D) tight

16-20 BBDBC