德尔格CO检测仪每隔10秒左右发光二极管闪烁一次,说明()。
A、仪器工作正常;
B、电源电压下降;
C、仪器工作不正常;
D、电路循环自检不正常。
参考答案:A
Eating a lot of _____ and vegetables ______ for your health.
A.fruit; is good
B.fruits; are well
C.fruits; are good
D.fruit; are well
上皮异常增生常见于
A.白斑B.口腔扁平苔薛C.天疱疮D.含牙囊肿E.牙源性角化囊肿