题干

“观察DNA和RNA在细胞中的分布”的实验顺序是(    )

①取细胞制片②用吡罗红甲基绿染色剂染色③水解④盖上盖玻片⑤冲洗涂片

A:①③②④⑤

B:⑤③④②①

C:②③④①⑤

D:①③⑤②④

上一题 下一题 0.0难度 选择题 更新时间:2019-03-06 04:39:18

答案(点此获取答案解析)

D

同类题5

学生会要表彰一批优秀学生,Tom想推荐他的同学John竞争最乐于助人奖(Most Helpful Student Award)。请以Tom的名义给学生会主席写一封推荐信。词数约80,不包括已给出的开头和结尾。
推荐信中必须包括下列要点:John
1、有礼貌,勤奋,乐于助人,常帮助同学学习
2、聪明,记忆力好,学东西很快
3、经常为希望工程募集物品,照顾老年之家的老人
4、电脑用得好,经常为帮扶俱乐部(the Helping Hands Club)从网上获取资料
5、上周,一个小男孩迷路,John将他送回家,男孩的父母很感激他。
Dear Sir
I would like                                                              
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
We will be glad if he can win the award.
Thank you
Yours faithfully
Tom
Best wishes for you!  Hope to see you soon!