到去年年底，中国加入世界贸易组织的过渡期才结束。( )
参考答案：对
The reason _____ he told me is _____ he was caught in the traffic jam .[ ]
A. why, that
B. that, that
C. what, why
D. /, /
人类每年需要从大自然中提取数以亿吨计的金属，其中提取量最大的是______；防毒面具的滤毒罐里用于吸附毒气的物质是______．
