They________extensiveandpossiblydangerousactualflighttraining.
A、undertakeB
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：WewishtocallyourattentiontothevalidityoftheL/C,sincethereisnopossibilityofL/Cextension.
Accordingtotheshipping_____itwillbeimpossibleforustoshipthegoodsinOctober.()
Don’ttrusteverything________youhavereadinthenewspapers.
_______foralongtime,mostofthecropsinthisareadiedfromlackingwater.
Totrade____thepeopleofalleountries____thebasisofequalityandmutualbenefitisourestablishedpolicy.
