Why cant Don call the professor himself？A．Because he is in the hospital.B．Because he has a

Why does the professor discuss the presence of zinc in paint pigments？A．To explain why som

Why cant the man tell the woman what the present is？A．Because the woman may think the pres

Why cant the large trees be popularly found indoors？A．The temperature is not suitable.B．Th

Why did the woman go to see the professor in the beginning？A．She wanted the professor to e

Why cant man prevent the world from being polluted？A．It"s because there are many developin

Why CANT the man come at the time the woman first suggests？A．He has a meeting.B．He"s going