题干
We all think it is Mr Wang as well as his parents that _______ for his son’s bad performance at school.
A：are to blame
B：is to be blamed
C：are to be blamed
D：is to blame
答案(点此获取答案解析）
D
，当
取最小值时，实数
的值是（ ）
”形太阳进行观察，纸盒上扎有圆形小孔，则她在半透明光屏上看到像的形状是（ ） 
