支配二腹肌前腹的神经是( )
A．面神经
B．上颌神经
C．下牙槽神经
D．三叉神经
E．迷走神经
参考答案：D
Grover Cleveland was the first president () in the White House.
A. got married
B. to get married
C. has got married
D. was married
设有区域D：x2+y2≤y，x≥0，f(x，y)在D上连续，且
求f(x，y)．
