21. Everybody has ________ responsibility to save water, if future generations are to enjoy ________ similar standard of living to the one we enjoy now.
A. the; / B. a; a C. /; the D. a; the
22. ________ is the kindness of the nurse that the patient can never be ________ to her.
A. So; too thankful B. Such; too thankful
C. So; that thankful D. Such; enough thankful
