( ) 21. She’ll be back ________ a week.
A. after B. in C. from D. at
( ) 22. My sister can’t dance, I can’t, ________ .
A. too B. also C. either D. neither
( ) 23. I suppose there will be ______ people and ______ pollution in the future.
A. fewer, fewer B. less, less C. fewer, less D. less, fewer
