by the age of什么意思？

by the age of的音标：by the age of的英式发音音标为：[bai ðə eidʒ ɔv]by the age of的美式发音音标为：[baɪ ði edʒ ʌv]...

By the age of two most children have begun to communicate verbally.大多数孩子两岁时就开始用说话沟通.By the age of sixteen he was the junior lightweight champion of Poland.16岁时他已经是波兰的青少年组轻量级冠军。By the age of seven he could write beautiful...