The writer has not directly stated, but would support the opinion that______.A．Astronauts

The writer has not directly stated, but would support the opinion that______.

A．Astronauts have taken a personal interest in the history of the Great Wall of China

B．the common people of the Qin Dynasty were the ones who provided the labor in constructing the Great Wall

C．work on the Great Wall was started before the Qin Dynasty came into existence

D．the Great Wall of China is a great human achievement and was probably worth the effort it took