They ________ extensive and possibly dangerous actual flight training.
B
句意：他们经历了大量的并且可能是危险的实际飞行训练。
翻译：WeadvisedyouinourletterofDec.1,thatwewouldliketoplaceatrialorderwithyoufor50piecesFlyingPigeonBicycles.
Welodge(声明)aclaim_______you_____theshort--weight.()
Thisisourbestprice,____whichwehaveconcludedmanyorderswithotherbuyersinyourcity.()