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问题 单项选择题

口腔变形链球菌的特点不包括（）。

A．血清型不同

B．微需氧环境生长最好

C．最适pH为4.2

D．在葡萄糖培养基中生长迅速产酸

E．能从蔗糖产生胞外多糖

答案

参考答案：C

选择题
方程组
x+y=1
x-y=-1
的解集是（　　）
A．{x=0，y=1}B．{0，1}C．{（0，1）}D．{（1，0）}
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阅读理解
阅读理解。
     This summer, Mary, Tom, Alan are going to have an ideal vacation. The followings are their plans for
the coming vacation.
 
Mary
Tom
Alan
Where
The Great Wall
Spain
Canada
When
The first week in June
The last day of May
July,  Monday 18th
Who
His parents
His best friends
His cousin
What
Going  hiking
Going  sightseeing
Visiting some famous
places in Beijing
Going shopping
Going  sightseeing
Going shopping
going camping
Watching bull-fight
spending time on the farm
rending videos at night
going  fishing
going  hiking
sleeping  a lot
How long
About one month
Only two weeks
Until  September
Transportation
By plane and bus
By boat and plane
By plane and train
1. Who is going hiking this summer? 
[ ]
A. Mary
B. Tom
C. Alan
D. A and C
2. What isn't Tom doing for vacation?
[ ]
A. Watching bull-fight
B. Going shopping
C. Going fishing
D. Going sightseeing
3. Who can visit the s Palace Museum (故宫) this vacation?
[ ]
A. Alan
B. Tom
C. Mary
D. Nobody
4. Whose vacation is the longest (最长)?
[ ]

A. Mary
B. Tom
C. Alan
D. We don't know

5. What's the same transportation are they going to take?
[ ]
A.Train
B. Bus
C. Boat
D. Plane
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