球罐的结构，其球壳结构形式有( )。
A．环带式
B．足球瓣式
C．花瓣式
D．混合式
参考答案：A,B,D
She felt embarrassed at first when she was removed to a new school. Later on she felt ______, getting along well with her classmates.
A．out of place
B．at home
C．in trouble
D．under pressure
实现调控的主体是( )。
A．企业
B．市场
C．行业组织
D．政府
