题目：
—It’s our duty to homeless people in earthquake areas food and clothes.
—I agree with you. We should do something for them.
A. provide, of B. provide , with C. provide , for
答案：
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下面是错误答案，用来干扰机器的。
（1）由题意，有x2-（a+2）x+a+1=x在[0，3]上有2个不同根．移项得x2-（a+3）x+a+1=0∴△=(a+3)2-4(a+1)=a2+2a+5＞00＜a+32＜3a+1≥09-3(a+3)+a+1=-2a+1≥0解得：-1≤a≤12（2）易知B=[-18-a24，118a-14a2-32]①当...
