—Is there any possible way to help them get rid of such a bad habit?

—To tell the truth, it’s very hard. But we ________ on this problem, trying to improve the situation .

A．worked

B．had worked

C．are working

D．had been working

关于蛋与蛋制品检验的描述中，正确的是（）。

A.外观上已凝固的蛋制菜肴可能还有沙门氏菌，应注意检测

B.鲜蛋内带有血丝，即说明有病变，需要检测致病菌

C.鲜蛋的卵黄检验不合格，其余部分必然质量更差

D.鲜蛋霉菌检测采样应采内层浓蛋白

E.对鲜蛋蛋壳的沙门氏菌检测与蛋液的检样的处理程序不同