正确的答案应该是D 这是考查倍数公式的单选题
常见的倍数考查有三种：A is +倍数+as + adj原级+B
= A is +（倍数-1）+比较级+than B
=A is +倍数+the +n.(size/weight/length/width ...) +of B
eg.The bag is three times as heavy as that one.
=The bag is twice heavier than that one.
= The bag is three times the weight of that one.
希望我的回答能对你有所帮助.