“全面检全面修”的检查范围和质量标准规定：铁路货车车门（）装置配件齐全、无破损。
参考答案：锁闭
笔直的窗帘轨，至少需要( ) 个钉子才能将它固定，理由是( ) 。
China won't be a fast-growing but fragile country. It has to develop it's military strength in order to make
any power think twice _____ trying to offend China's key interests. [ ]
A. before
B. when
C. while
D. until
