A：-3
B：-2
C：2
D：3
“人间四月芳菲尽，山寺桃花始盛开，”造成这一差异的环境因素是（ ）
60+7=____ 75-5=____ 20+30+40=____
50+21=____ 76+9=____ 4+（9+20）=____
29+6=____ 86-30=____ 66-6-50=____
100-10=____ 81-（7+3）=____ 83+10-50=____
No. 1 Middle School
Don't run in the hallways
Don't bring food into the classroom.
Don't listen to music in class.
You have to wear a uniform.
No. 2 Middle School
Don't bring food into the classroom
Don't wear a hat in class.
Don't go into the classroom without the teacher.
No. 3 Middle School
Don't listen to music in the classroom.
Don't run in the hallways.
You have to wear sports shoes for gym class.
____ ____ is she?
如果命题“￢（p或q）”为假命题，则（ ）
