There is a grammatical mistake in the following sentence. Which choice identifies this mistake?Thirty-two patients underwent CT and MRI examinations were analyzed retrospectively. A: patients B: underwent C: examinations D: analyzed

The explorers had to ___ much suffering. A: undergo B: go C: underwent D: undergone

She much suffering during her childhood. A: underwent B: underline C: undertake D: underestimate

The judge ___his opinion<br/>and declared that the accused was not guilty. A: underwent B: reversed C: undid D: masked

In the sentence “John underwent major heart surgery”, John is the（ ）. A: agent B: grammatical subject C: logic subject D: predicate

Like many of her generation, the lady _________ a lot of hardships throughout her life. A: underwent B: undergo C: undergoing D: undergoes

In the 1920s, Dan played by Mei Lanfang gained great popularity. Peking Opera then underwent a major shift from an emphasis on aesthetic values to an emphasis on moral education.

This changed during the Han dynasties when the sickle underwent changes and developed into zhi and ai. Archaeological findings indicated that the iron sickle was in existence during the Warring States Period.（ ）

Like many of her generation, the lady _________throughout her life. A: undergo a lot of hardships B: undergone a lot of hardships C: underwent a lot of hardships D: suffer a lot of hardships

What did the receptionist say about the hot water system? A: It was out of electricity at that time. B: It underwent a technical problem this morning. C: It had broken down earlier last week. D: It would be fixed by 8 tonight.