I have a laptop _____ I don't often use it. [ ]
A. and
B. so
C. or
D. but
答案:D
不利于预防骨质疏松症的生活方式包括()
A.合理的全面均衡营养
B.酗酒
C.戒烟
D.经常参加户外活动,增加日照
E.适当的性生活