"Where's Uncle Wang?" 　　

"Look! He is over there. He and Tom _______ at a machine now." [ ]

A. is working 　　　

B. work 　　　　　　

C. worked 　　　　

D. are working

砒霜引起的食物中毒可采用特效解毒剂巯基类药物急救。( )