问题 填空题

染色体是由DNA和蛋白质两种物质组成的.[______].

答案

染色体是细胞核中容易被碱性染料染成深色的物质,染色体是由DNA和蛋白质两种物质组成;DNA是遗传信息的载体,主要存在于细胞核中,DNA分子为双螺旋结构,像螺旋形的梯子.它由两条长长的、互相盘绕的链组成,构成双螺旋结构,上面有特定遗传效应的片段叫做基因.基因决定生物的性状.一条染色体有一个DNA分子组成,一个DNA分子上有许多个基因.染色体主要是由DNA和蛋白质两种物质组成.

故答案为:A.

改错题

第二节:短文改错(共10小题;每小题1. 5分,满分15分)

此题要求改正所给短文中的错误。如有错误(每行只有一个错误),如无错误,在答题卡相应的位置上画一个勾(√);如有错误(每行只有一个错误),则按下列情况改正;

此行多一个词:把多余的词写在答题卡相应的位置上,用斜线(﹨)划掉。

此行缺一个词:在答题卡相应的位置上写出该加的词,并附带前(后)词。

此行错一个词:在答题卡相应的位置上写出该错词和改正后的词。

注意:原行没有错的不用改。

A 60-year-old Australia woman jumped onto the back                        76. ___________

of a 4-metre crocodile stop it from killing a 34-year-old                  77. ___________

man. The crocodile grabbed one man as he was sleeping                   78. ___________

in a tent at a beaches campsite in Australia. The crocodile                79. ___________

entered the tent around 4 a. m. Monday and dragged                       80. ___________

the man outside. The woman, that was camping nearby, saw             81. ___________

what was happening and jumping onto the crocodile. The crocodile 82. ___________

then let the man go and turned on the woman, pulling him                      83. ___________

towards the water. Luckily a third person shot                                 84. ___________

the crocodile death just in time, saving the woman.                          85. ___________

选择题