21、The driver was at ______ loss when _____ word came that he was forbidden to drive
for speeding.
A. a; the B. /；/ C. the; the D. a；/
22、Without the friction (摩擦力) between feet and the ground, people would ____ be able
to walk.
A. in no time B. by all means C. in no way D. on any account
