望小儿指纹，可用于辨别疾病轻重的是
A．红紫B．三关C．浮沉D．淡浓E．以上均非
参考答案：B
More than 30 years ago, （）that the region was rich in natural resources。
A.people did littleknow
B.people little know
C.littledidknow
D.little did people know
有A、B、C三个数，已知a×b=24，a×c=36，b×c=54，求a+b+c=
A．23
B．21
C．19
D．17
