(x+1)4的展开式中x2的系数为
A：4
B：6
C：10
D：20
More historical buildings in the old town will fall down________we try our best to protect them.
成为探索建设社会主义道路的良好开端的是（ ）
It's six thirty in the evening. My parents are cooking dinner in the kitchen. My father is cooking fish. It looks great. My mother is washing some vegetables and fruit.She wants to cook some soup with tomatoes and make fruit salad. I love the fish. It's yummy. I also love tomato soup and fruit salad.
已知2是关于x的方程x-2a=0的解，则a的值为（ ）
