A、  B、  C、  D、  D仔细观察可以发现，一位男士和两位女士正在实验室中仔细观察着什么，而且旁边有显微镜和试管。

(A)They’re opening their backpacks.
(B)They’re getting out of a vehicle.
(C)They’re lined up alongside a bus.
(D)They’re walking across the street.

(A)A man is handing out lab coats.
(B)A microscope is being adjusted.
(C)A test-tube is being set down.
(D)A woman is writing on a notepad.