公民履行兵役义务的形式有哪些？
参考答案：现役士兵；现役军官；士兵预备役；预备役军官。
As we all know, it was ____ that resulted in the terrible car accident.
A. because of her carelessness B because she was careless
C. her being careless D she was so careless
石油是工业的血液．世界上石油储量最大、产量和输出量最多的地区是（ ）
A．中东地区
B．俄罗斯
C．中国近海
D．墨西哥湾
