A:m>7
B:m≥7
C:m<7
D:m≤7
计算
①5.32÷3 916 ×7.125﹣(29 747 ﹣29.36);
②(14.25﹣7 512 )×2 313 ÷(1 712 +87.5%)÷(14 34 ×8 229 ).
If you feel ____ (stress), try to be ____ (relax).
在凸透镜的主轴上离透镜1.5f到2f处横卧一根粗细均匀的细杆AB,f为凸透镜的焦距,则细杆成像的位置在( )
To keep children away from danger,we warn parents ________ children at home alone.