读图“我国东部冬小麦种植区内收获期等值线图”，据此回答问题。

小题1:我国冬小麦最主要产区及其农作物熟制的叙述，正确的是

A．陕甘宁地区一年一熟

B．冀鲁豫地区两年三熟

C．云贵川地区一年两熟

D．鄂湘赣地区一年三熟小题2:导致R地和Q地等值线延伸方向不同的主要因素分别是

A．纬度和地形

B．纬度和距海远近

C．地形和季风环流

D．距海远近和季风环流

Channel 13 is primarily used for ship to ship communication. Channel 13 is also authorized for（）.

A.coast to aircraft operational communications

B.aircraft to ship operational communications

C.lock & bridge communications

D.aircraft to ship navigational communications