...improving the yield of the crop...提高农作物产量When the summer crop is ripening, the autumn crop has to be sowed.夏季作物成熟时, 就得播种秋季作物.The islanders could barely survive without an export crop.没有出口作物，岛上的居民几乎无法生存。It also demonst...
Skipping is one of the most enjoyable aerobic activities.跳绳是最有乐趣的有氧健身运动之一。Walking, done in the right way, is a form of aerobic exercise.走路，如果方法正确的话，也是一种有氧健身运动。Aerobic exercise helps to build up stamina.有氧健身操有助于增强耐力....
He looked fixedly at Nella and started back.他目不转睛地看着内拉,接着往后一缩.Nella stood at the end of the gangway.内拉站在舷梯尽头.At best Nella would be an invalid; at worst she would die.内拉往好里说会落下残疾，往坏处说可能会生命不保。At best Nella would be an inv...