问题
解答题
先化简（
|
答案
原式=
×（a2-1）-a a-1
×（a2-1）1 a+1
=a（a+1）-（a-1）
=a2+a-a+1
=a2+1．
∵若使分式有意义，则a2-1≠0，即a≠±1．
∴当a=0时，原式=0+1=1．
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先化简（
|
原式=
×（a2-1）-a a-1
×（a2-1）1 a+1
=a（a+1）-（a-1）
=a2+a-a+1
=a2+1．
∵若使分式有意义，则a2-1≠0，即a≠±1．
∴当a=0时，原式=0+1=1．
A. The children don't study hard, they fall behind others.
B The teachers often left the children behind.
C. The children always sit at the back of classroom.
D. The children's parents are working far away from them.
3. What did the premier do after he visited Yang Saike's home? [ ]
A. He held Yang in his arms.
B. He asked the local governments to care for the "left-behind' children.
C. He praised Yang for his hard work.
D. He shed tears with sad families.
4. Which of the following is NOT TRUE? [ ]
A. Yang Saike's parents usually go home after working.
B. Premier Wen has encouraged the whole nation to fight against the disasters.
C. Grandpa Wen always thinks of the people first.
D. The governments would do something to protect and care for people