A lack of magnesium causes muscles to go into spasm.缺镁会导致肌肉痉挛。Magnesium is the nutrient element in plant growth.镁是植物生长的营养要素.The water contains high amounts of magnesium.这水含有大量的镁....
在纸板上涂两三层清漆使其变硬。Give the cardboard two or three coats of varnish to harden it.这种材料需要有更高的温度和压力才能凝结变硬。The material requires higher temperatures and pressures to set hard.雪成冰后变硬了.The snow hardened until ice was formed....