扫描二维码，直接登录
题库 / GMATLA-CR-8
Telomerase is an enzyme that is produced only in cells that are actively dividing. For this reason it is generally absent from body tissues in adults. Bone marrow is an exception to this rule, however, since even in adults, bone marrow cells continually divide to replace old blood cells. Cancers are another exception, because their cells are rapidly dividing.
The information provided most strongly supports which of the following?
Telomerase is the only enzyme that is present in cancerous cells but absent from cells that are not actively dividing.
In children, the only body tissues from which telomerase is absent are those in which cells are not rapidly dividing.
The presence of telomerase in bone marrow is no indication of bone marrow cancer.
Cancer of the bone marrow develops more rapidly than cancer growing in any other kind of adult tissue.
The level of telomerase production is always higher in cancerous tissue than in noncancerous tissue.
B 条件结论型；T只存在于active dividing的cell里。
Only之后的为必要条件，也就是说T能推出active dividing的cell，
没有T不能推出别的，因为不是逆否命题
Bone marrow 骨髓
No indication.........不能作为是否有癌症的指标。。。
是不是因为 t会存在于分解的快的细胞里， bm里的细胞分解快， 癌细胞分解的快。但是因为bn细胞本来分解的就快，所以它不需要癌变也可能有t存在。
a说t是唯一一种在不分裂的细胞里没有，但是在癌细胞里有的物质。无关
b说在小孩体内唯一一种组织里没有T的是那些不快速分裂的细胞。 无关
c说在bone marrow里的癌细胞比其他成年人体内的组织里的细胞发展的要快。与t完全无关
d说在癌细胞里的t总是要比非癌细胞里的要高。 文中没有出现比较。
原文描述的是:虽然T在成人中缺乏，但是在BM中有，因为BM也一直在分裂。然后又说cancer虽然一直也在分裂，但是并不是因为有T，它是一个例外。我想c选项其实表述的意思就是telomerase和cancer没关系，也就加强了原文中的cancer 是例外的意思。
D选项 原文没有给出“两者加和”变得更强的意味
B 选项 原命题成立 否命题不一定成立
我觉得应该是原文根本没有提到children吧，这里默认children的器官都应该是divide rapidly的，但文中并没有说。children并不是adult的反义词
登录 或 注册 后可以参加讨论