当四边形的两条对角线满足条件：（ ）时，顺次连接它的各边中点可以得到一个菱形。
对角线相等
In ______ eyes of my parents, a knowledge of English is ______ must in the world today.
A．the;不填
B．the; a
C．不填; a
D．不填;不填
一般在春末夏初采的药材是
A．根及根茎类药材B．全草类药材C．果实类药材D．茎木类药材E．皮类药材
