英语，请高人帮忙！多谢！

1. why did man think salt was much like friendship?
From the experience men learned that salt itself lasts; it helps to preserve food. The true properties of salt gave rise to other beliefs about it. So men thought it was much like friendship, since friendship in their mind should be everlasting. Many old customs linked salt with friendship. Salt was often given as a present to a friend in his new home.

2. Why were the doctors easy to be injured by the X-ray?
At first the doctor did not understand how powerful the rays were and many of them were injured, losing a finger or an arm through exposure to X-rays when they were using the machines.

3. How do you understand the saying “ a great man makes his own good luck”?
Good luck is not something random that befalls us. It is something that we grab as it passes by. “ A great man makes his own good luck” indicates that one of the differences between a great man and the rest of us. When g