Question

All plant cells are capable of taking up water．Even dead ones do to a certain degree．Absorption of water by dead cell walls makes wood become larger．In common land plants,the living cells of roots take up most of the water．Land plants without roots do exist,however．Those greenish-yellow lichens（苔藓）you see on rocks in the high mountains have no roots．Half a billion years ago,when water plants started to enter the land,the first land plants did not have roots． 　　Even among the flowering plants,one finds roofless forms．These flowering plants are“the higher plants”because they evolved（进化）recently and are thus considered higher on the evolutionary scale（进化树）．In the Peruvian desert,there grows one of these rootless higher plants,a bromeliad．It is a relative of the pineapple．Even if this plant had nots,they would be of no use,because where the plant grows,it never rains．The plant gets its water only from the dew （露水）it collects at night,when its leaves cool off．Such rootless plants,of course,can be moved with ease,hut they will only grow when they are placed out in the open．If they are placed too near a house,the radiation from the heat of the house prevents the leaves from cooling and so prevents dew from forming,and the plant dies．In the southern United States and in Puerto Rico,one sees bromeliads growing high above the streets on the insulation（绝缘物）of electric wires．These plants get their water from rain,and the only soil they ever come in contact with is the dust that may blow on their leaves． (1) Wood becomes larger because of ________ [　　] A． dead cell walls B． water entering dead cells C． the growth of cells D． the death of cells (2) From the passage we know that the evolutionary scale is graded according to ________ [　　] A． evolutionary cycles B． heights and depths C． time D． kinds (3) The“bromeliad”is a plant that ________ [　　] A． has useless roots B． is a pineapple C． can grow anywhere D． takes up water through its leaves (4) The most suitable title for this passage is“________” [　　] A． Absorption of water by plants B． Rootless plants C． Plants in the desert D． Higher plants

Answer 1

答案：1．B;2．C;3．D;4．A;
解析：

(1)	从文章第一段可知。植物吸收水分而使其生长。普通陆地植物的根部活细胞吸收水分，从而促进细胞生长。
(2)	根据文章第二段第二句。这些开花的植物是“较高的植物”，因为它们是最近进化而成。recently是关键词。说明这里所说的进化分为过去和最近。把进化形象地比作树的话，开花植物应看作是树的上端的等级。
(3)	从第二段第三句话可知。这种植物虽然有根，但也没有起到作用，因为这种植物生长的地方从不下雨。它是靠叶子来吸收水分的。
(4)	整篇文章谈论的是植物吸收水分的情况