小华同学配制50g溶质质量分数为20%的NaCl溶液，操作流程如图：

（1）小华同学应称取氯化钠的质量是____ g．

（2）指出图示操作中的一处错误：____．

（3）在用托盘天平称取氯化钠的过程中，发现指针偏向分度盘右侧，他接下来的操作是____ ．

（4）如果小华配制的NaCl溶液的溶质质量分数小于20%，则造成此误差的可能原因有____ 　．

A．装入试剂瓶时，烧杯内残留少量液体     B．量取水时仰视读数

C．向烧杯中倒水时，有少量水溅出烧杯外     D．称量纸上残留少量氯化钠．

④无限增殖    ②代谢速率减慢    ⑨细胞膜上糖蛋白减少   ④具有浸润性   ⑤产生大量的毒素

综合短文填空，选择正确单词填入相应的空格.

    People never travel as often as today in China. In the past, few people could travel on ____ to other countries. But today more and more Chinese people travel ____they now are becoming richer and have enough money for travel. The special plane for tourists ____ travel____ expensive than ever before. Most people enjoy ____ countries that are different from ____own. They also like to meet people and eat new food. Tourism causes many____  in Chinese people’s lives. People build new hotels and ____some people____ interesting places to ____ . Now Tourism is a big business.

开花植物种子的营养储存方式有两种，一种是将营养储存在子叶中；另一种因没有子叶，所以将营养储存在胚乳中．（判断对错）