用铝合金制作钥匙是利用铝合金( )
A.熔点低
B.不易腐蚀
C.硬度大
D.密度大
制作钥匙需要钥匙本身经得起扭转和外力的,所以用铝合金制作钥匙是因为铝合金的硬度大.故选C
Richard was very strict with his two daughters,______them to compete against each other.
A.to train
B.trained
C.and trains
D.training
押品通过降低违约率和违约损失发挥风险缓释作用。