【单选题】Which of the following descriptions is INCORRECT?
A.
Second-hand clothing and household articles may be economical.
B.
Prices vary considerably in the US.
C.
Most second-hand clothes are of rather good quality.
D.
You may go to a 'loan closet' to loan clothes at a low cost.
【简答题】My father often said that it was only because my grandmother was so economical that the wolves were kept at bay 。
【单选题】What's the reason for the popularity of second-hand items?
A.
People have a preference for unconventional things.
B.
People think old clothes are better than the new.
C.
People like second-hand items because they are cheap.
D.
The young people like to go with the stream.
【简答题】由一个基本铰接三角形依次增加二元体而组成的桁架称为_______________,由几个简单桁架按照几何不变体系的组成规则组成的桁架称为_____________,按上述两种方式以外组成的其它静定桁架称为_____________。