—You _____ be very tired after the long flight.        

—Yeah, though I am tired, I feel excited and happy.            [ ]

A. must  

B. probably  

C. can’t    

D. can

下列各组中全部都属于自然资源的是

A．土地、阳光、钢铁

B．铜矿、煤炭、电

C．森林、木材、纸

D．土地、森林、铁矿