21. —Call me at six tomorrow morning.
—Why so early? I _____.
A. will sleep B. will be sleeping C. have slept D. was sleeping
22. Lake Tianchi is _____ highest volcanic lake in the world and it covers _____ area of 10 square kilometres.
A. the; an B. a; an C. /; an D. the; a
23. The weather was _____ cold that I didn’t like to leave my room.
A. really B. too C. so D. such
