小题1:Jack wants to go to the zoo early next Thursday．The zoo will open at__________．

A．9：00 a．m．

B．10：00 a．m．

C．4：00 p．m．

D．5：00 p．m．小题2:If visitors cannot see the animals, the animals may be______．

A．playing

B．eating

C．acting

D．sleeping小题3:Jack is eight years old．He goes to the zoo with his 58-year-old grandfather．How much should they pay for visiting the zoo?

A．$18．

B．$22．

C．$28．

D．$32．小题4:What should we do in order not to frighten the animals?

A．We should ride bikes．

B．We should keep quiet．

C．Ｗe should feed the animals．

D．We should keep the zoo clean．

以出芽方式释放的病毒具有下列哪些特征（）

A.对乙醚等脂溶剂敏感

B.对温度抵抗力较弱

C.以融合方式穿入细胞

D.病毒可带有宿主细胞成分

E.易形成缺陷病毒