【简答题】We started early in the morning( )and before dark we reached the village.
【单选题】We started early before dark
【简答题】We started early in order _______ we could catch the first train.
【判断题】We started early in the morning, and before dark we reached the village.
【多选题】表面结实光滑,有较强光泽的物体容易反射成像,而反射成像的形很容易被
【简答题】总产量、平均产量、边际产量的含义及表示?