A:鸟嘌呤(G)
B:胞嘧啶(C)
C:尿嘧啶(U)
D:腺嘌呤(A)
水是人类宝贵的自然资源.
随着生活水平的提高,人们的饮食结构和饮食习惯正趋于多元化,在此过程中,肥胖病患者呈现上升趋势。其中,青少年和儿童肥胖患者也逐年增多。“关注肥胖,增进健康”日益成为人们茶余饭后的热门话题。请你结合所学知识回答下列问题:
Learning English online
Ways to learn English
English magazines, newspapers and radio
Various kinds of English learning1.
Benefits of online learning
People around the world can visit them 2.
People can get answers instantly on the Internet.
People can learn what they need anytime and search for useful3 without leaving home.