下半身青紫见于
A．室间隔缺损B．动脉导管未闭合并肺动脉高压C．房间隔缺损D．法洛四联症E．动脉导管未闭
参考答案：B
能被吸入人体肺泡的粉尘对人体的危害性最大。
Jenny has ______ English book. ______ book is on her desk. [ ]
A. a, The
B. an, The
C. the, A
D. an, A
