recognize their mother's voice among a group of women.

　　A. suspect B. compromise C. discriminate D. inspect

　　(　　)26. ________ with heavy loads of teaching ________ he later became an easy target of the flu.

　　A. So tired was the teacher; that B. The teacher was so tired; which

　　C. Tired as the teacher; that D. Such was the tired teacher; which

　　(　　)27. -Why not turn to Kevin? He saw what happened, so his is the only ________ account.

　　-The problem is that he has refused to say anything about the accident.

　　A. tentative B. controversial C. authentic D. arbitrary

　　(　　)28. Granny always keeps her cellphone switched off ________ she's expecting a call.

　　A. since B. unless C. once D. when

　　(　　)29. -________ makes your son feel blue today?

　　-________ to watch his favourite cartoon Paw Patrol

　　A. What it is that; To be forbidden B. What is that; Forbidden

　　C. What is it that; Being forbidden D. That is what; Having forbidden

　　(　　)30. Using AI, many companies are now conducting experiments that ________ possible just a few years ago.

　　A. would have been B. might have been

　　C. shouldn't have been D. couldn't have been

　　(　　)31. The study, from academics at Harvard, claims ________ the first clear evidence showing that when temperatures go up, school performance goes down.

　　A. to have produced B. to produce C. producing D. being produced

　　(　　)32. Though scientists get closer to understanding why we age, the reason for different aging rates among individuals remains only ________ understood.

　　A. concretely B. thoroughly C. vaguely D. flexibly

　　(　　)33. -The president will come to attend your lecture at 10：00 tomorrow.

　　-I'm sorry, by then my lecture will have just ended and I ________ my fans in my office.

A. have met B. will have met C. will meet D. will be meeting