21. — The little boat is ______ safe. Don’t you think so, Mike ?
— No worries! I’ve been on this boat dozens of times.
A. something but B. nothing but C. anything but D. everything but
22. — What do you think of Peter?
— He ______ be really difficult to get along with even though he’s a nice person in general.
A. shall B. should C. must D. can