2×4____45÷9 25____4×7 25÷5____5×1
72÷9____6 63÷7____3×3 54÷9____2×4
- Where are you going, Bob?
- To go hiking. Eric ________ for me at the school gate!
达菲是治疗甲型H1N1流感的一种良药。达菲的化学式是C16H31N2PO8,则下列说法正确的是( )
已知a∈R,i是虚数单位,若z=a+ 3 i,z• z¯ =4,则a=( )
“七八个星天外,两三点雨山前。”这两句用对偶的手法写出了夏夜特有的景象。