535.
Over the past 30 years，China significant changes in comprehensive national strength
thanks to the reform and opening-up policy.
A. witnessed B. were witnessing
C. has witnessed D. will have witnessed
答案 C
536.
--- Ring me at six tomorrow morning, will you?
--- Why that early? I ______ .
A. will be sleeping B. have slept C. have been sleeping D. will sleep
答案 A
