人体的免疫系统是抵御疾病的主要屏障。The immune system is our main defence against disease.这些人造屏障将会确保提供高度的保护。These man-made barriers will ensure a very high degree of protection.燕山是北京的天然屏障.The Yanshan Hills provide a natural defence for Be...
He was wont to rise early.他惯常起得很早。He was wont to say that children are lazy.他常常说小孩子们懒惰.He went to bed much earlier than was his wont.他(那晚)就寝的时间比平常早了很多。He was wont to fall asleep after supper.他老是吃完晚饭就打盹。Paul woke early, a...