俄罗斯建筑的民族特色是什么？
参考答案：
风格独特的民间木建筑：水平叠木、屋面坡陡、空间狭小、室外楼梯
The old couple has ____ a lot since their only son was killed in an accident two years ago.
A．looked through
B．gone through
C．got through
D．passed through
党的（）提出了推进生态文明建设的内涵和目标任务，十八届三中全会明确了生态文明体制改革的主要任务。
A.十六大
B.十七大
C.十八大
D.十八届一中全会
