1.在下列图形性质中,平行四边形不一定具备的是( )
| A. | 对角线相等 | B. | 两组对边分别平行 | ||
| C. | 两组对边分别相等 | D. | 对角线互相平分 |
16.下列计算正确的是( )
0 297003 297011 297017 297021 297027 297029 297033 297039 297041 297047 297053 297057 297059 297063 297069 297071 297077 297081 297083 297087 297089 297093 297095 297097 297098 297099 297101 297102 297103 297105 297107 297111 297113 297117 297119 297123 297129 297131 297137 297141 297143 297147 297153 297159 297161 297167 297171 297173 297179 297183 297189 297197 366461
| A. | $\sqrt{27}$÷$\sqrt{3}$=9 | B. | 3$\sqrt{3}$-2$\sqrt{3}$=1 | C. | ($\sqrt{7}$+$\sqrt{3}$)×$\sqrt{10}$=10 | D. | $\frac{1}{\sqrt{2}-1}$=$\sqrt{2}$+1 |