由于燃料油循环能防止冻结、减少油温降低便于控制油压的特点，因此燃料油循环量是越大越好。（）
参考答案：错
函数f(x)＝(x2＋x＋1)ex(x∈R)的单调减区间为________．
翻译画线部分。
1. I want to buy 礼物 for my family. _________________
2. I want to go shopping today. _________________
3. They sit and sit. _________________
4. Yes, I know. My tail hurts. _________________
