21. These young seedlings will require _______ carefully.
A. look after B. looking after C. having looked after D. to have looked after
22. The manager promise to keep me ______ of how our business was going on.
Ato be informed B. informed C. on informing D. informing
23. He is one of those people ______ every body will find ______ hard to please.
A. that, being B. whom, / C. who, is D. which, to be
