用“＞”、“＜”或“=”完成下列各式。

1. eight _________ seven －one

2. nine _________ one

3. ten _________ six

4. two + three _________ five

5. six + three _________ ten

6. eight －two _________ seven

7. nine －four _________ four

8. five + two _________ seven

下列各项中，属于消化道传染病的是 [ ]

A、肺结核  

B、流行性乙型脑炎  

C、血吸虫病    

D、细菌性痢疾