做DNA粗提取和鉴定实验时，实验材料用鸡血而不用猪血的原因是[ ] A．鸡血的价
题型：选择题
问题：
做DNA粗提取和鉴定实验时，实验材料用鸡血而不用猪血的原因是[ ]
A．鸡血的价格比猪血的价格低
B．猪的红细胞没有细胞核，不易提取到DNA
C．鸡血不凝固，猪血会凝固
D．用鸡血提取DNA比用猪血提取操作简便
题型：选择题
阅读理解。
This is a boy. His name is Tom. He has a nice cat. It is an English cat. His friends are Lucy and Mike.
They have cats, too. Their names are Mimi and Maomao. They are Chinese cats. The English cat is five.
The Chinese cats are three. They like their cats.
Today they can't find the English cat and the Chinese cats. They ask an old man, "Where are our cats?" "I don't know." He says, "Are they in the tree?" Tom and Mike say. "Listen, listen!" Lucy says.
"Mi
aow, miaow……." " Oh, over there." They go to the tree, and carry (抱) them down.
根据短文内容，判断下列句子正（T）误（F）。
( )1. Tom has a good English cat.
( )2. Tom has four friends.
( )3. The English cat is three and the Chinese cats are five.
( )4. Tom and his friends have six cats.
( )5. Their cats are in a tree.