对角线相等且互相垂直的四边形是正方形．______．
对角线互相垂直且相等的平行四边形是正方形；或对角线互相垂直平分且相等的四边形是正方形．
故答案为：错误．
因产品质量造成损害赔偿的诉讼时效期间是______年。
A．1
B．2
C．4
D．10
Most of us think of sharks as dangerous, owing to lack of information rather than fear.
A．due to
B．because
C．as
D．for
