图示桁架中零杆的个数为（）。
A.7
B.8
C.9
D.10
参考答案：C
解析：
根据零杆判断法，有九根杆是零杆。
注意： NHA=NHE=0
The generative linguist is interested not only in ______ language but also in explaining language. In other words, they attempt to find the what as well as the why in the study of language.
据班固《汉书•百官公卿表》载“县令、长，皆秦官，掌治其县。……大率十里一亭，亭有长。十亭一乡，……”以下解读正确的是（）
A.秦亡后，县令、长在汉初继续留任
B.秦朝每县掌治100个亭
C.汉朝县扩大辖区，掌治100个乡
D.汉代县制大体沿用秦朝制度
