产品标准规定要求板、毡制品中纤维平均值应小于等于（）。
A.7.0µm
B.0.7µm
C.17µm
D.70µm
参考答案：A
Great changes have taken place in that school, it is no longer ________ it was 20 years ago, ________ it was so poorly equipped.
A．what; when
B．that; which
C．what; which
D．which; that
关于胡某与皮革公司订立的合同的效力，下列说法正确的是( )。
A．无效
B．有效
C．皮鞋公司追认后才有效
D．由皮鞋公司与皮革公司协商确定
