下列有关生物学实验原理和技术操作的叙述中，正确的是（ ）
A：研究人类遗传病的遗传方式，一定要调查患者家系的情况
B：在探究影响酶活性的因素时，温度、酸碱度、使用试剂的量等都是自变量
C：西瓜汁中含有丰富的葡萄糖和果糖，可用作还原糖鉴定的代替材料
D：换高倍镜后因视野较暗，应调节粗准焦螺旋
根据短文，判断正误。
My name is Ted Pike. I am a worker in a big store. I don't work in the morning. I only work at night. Every morning I come home at about half past six. I have breakfast at seven. After breakfast I go to bed. I get up at about half past two. I have lunch at a quarter to three and supper at twenty to eight. Then I go to work at a quarter past eight. I start work at nine. I look after the store every night. I like my work very much.
读课文《童年的发现》，说说句中省略号的作用
费奥多罗夫！……你立刻从教室里出去！……
