double crossover

基本解释

If you consistently over-reach on your backstroke pull, double-arm makes this very tough to do, because you have to cross your arms during the recovery to accomplish that.
如果你总是在仰泳划水的时候手臂过肩线，那么这个双臂练习就会让你很难做到，因为你必须在移臂时手臂交叉才能做到那样。
A series of double-blind, randomized, cross-over, healthy volunteer studies have been conducted to avoid the confounding effects on cognition such as those produced by changes in seizure frequency.
为了尽量减少如癫痫发作等其它因素对认知功能的影响，既往完成了许多健康志愿者参与的随机双盲交叉研究。