A、 Use the heart-valve taken from a dead person to repair it.
B、 Put in pieces of man-made heart-valve to make it normal.
C、 Replace it with another heart taken from a dead person.
D、 Get it repaired with a really strong pump.

【正确答案】 A

【答案解析】解析：题目问的是如果心脏的损伤不是很严重，我们应当怎样做。选项A的内容与原文中“we put in pieces of natural heart—valve”是一个意思，故选A。

A、 An animal's body.
B、 Another person who has just died.
C、 A person who has more veins than he really needs.
D、 The patient's own body.

【正确答案】 D

【答案解析】解析：题目问的是用来替换受损动脉的血管来自哪里。由对话可知“If a damaged artery is not too big，we replace it with a piece of veins than it really needs”意为：用不是很重要部位的血管去替代受损的动脉。因此，应该是病人自己的血管而不可能是来源于动物或其他的死者，故选D。

A、 They can operate the heart-lung machine.
B、 They have designed the heart-lung machine.
C、 They can make the blood continue to flow round the body.
D、 They do the Work of both the heart and the lung.

【正确答案】 B

【答案解析】解析：题目问的是在做心脏手术时，工程师帮助了我们什么。由原文可推断出工程师对我们的帮助在于发明了心肺机。故选B。

A、 The machine keeps the blood warm enough.
B、 The machine pushes the blood back into the vessels.
C、 The machine works very gently.
D、 The heart is empty of blood.

【正确答案】 C

【答案解析】解析：题目问的是当血液经过心肺机时，血细胞为何没受到损伤。根据定位句可知，是因为机器在工作的时候，非常地温柔，故选C。

A、 His heart and lungs are badly damaged.
B、 His blood cells are seriously damaged.
C、 He is not breathing and his heart is not beating.
D、 His heart and lungs have stopped working.

【正确答案】 C

【答案解析】解析：题目问的是问过去人在什么状况下常常被认为死亡。由原文可知“If you aren’t breathing，and if your heart isn’t beating，you are dead”，故选C。