答案:D
------ What do you think of the English dictionary?
------Not bad. You can’t find ______ in the bookstore.
A.a good one
B.the good one
C.a better one
D.the best one
采用空气层隔声可以提高隔声效果。那么,空气层的最小厚度和最佳厚度分别是多少()
A.最小厚度2cm,最佳厚度4~5cm
B.最小厚度6cm,最佳厚度7~8cm
C.最小厚度8cm,最佳厚度10~15cm
D.最小厚度5cm,最佳厚度8~12cm