唾液维持口腔pH是由于唾液中含有
A.免疫球蛋白
B.黏蛋白
C.大量的可产酸的细菌
D.如重碳酸盐缓冲系的多种缓冲体系的存在
E.淀粉酶
参考答案:D
—He got up as early as possible________he could get to school on time.
A.such that
B.in order to
C.so as that
D.so that
傈僳族的特色活动是()。
A.射箭
B.荡秋千
C.拉歌
D.赛马