双飞的英文：
n. dual instruction

参考例句：

"And now, in the Eighth-month, yellowing butterflies Hover, two by two, in our west-garden grasses"
八月蝴蝶来,双飞西园草。

dual是什么意思：
adj. 双的；双重的
n. 双数；双数词

His dual role as composer and conductor.
他兼作曲家及指挥的双重身分。

Dual-color fruit coffee
双色水果咖啡

Dual moisture detection probes to eliminate false alarms
双重防潮保护的探针能够避免警报失灵或误报

This dual tug is apparent in the whole movement of expatriation
这种两面周旋的态度在整个寄居海外运动中极为明显。

Dual to the bad weather, I did not test.
由于坏天气，我没有测得结果。