A:PBr3、NO2
B:CH4、SCl2
C:BF3、SO2
D:H2O,CS2
-________ is it from the bus stop to the train station? -Two kilometers.
请回答下列的问题.
The first question is as as the second one. I can answer them easily.
甲、乙、丙演示图,显示了森林、草地所具有的哪些作用( )
①防风固沙 ②防止水土流失 ③涵养水源 ④维护生物多样性