118,199,226,( ),238
A.228
B.230
C.232
D.235
参考答案:D
解析: 二级等比数列变式。相邻项作差可以得到8l,27,(9),(3)。故选D。
代表了釉质周期性生长的速率()
A.釉丛
B.釉梭
C.釉板
D.釉牙本质界
E.釉质的生长线
Look at the sweat on her face. She________the house since she got up this morning.[ ]
A. is cleaning
B. has been cleaned
C. was cleaning
D. has been cleaning