重点讲解：
1. set sail 启航；开船；
He loaded his vessel with another cargo and set sail.
他给自己的船装上另一批货后便启航了W%)0]7(+FR。
2. derive from （使）起源于；（使）来自；
Their numerical system, derived from the Babylonians, was based on multiples of the number six.
他们的数制源自古巴比伦人，以数字6的倍数为基数pya(A9m[tD&.v#p。
3. be close to 近的；接近的；
The children are close to each other in age.
这些儿童彼此的年龄很接近4||aS~.@S7。
4. take part in 参加；参与；
Six theatre companies have been selected to take part in this year's festival.
已选定六个剧团参加今年的戏剧节MMoa]Xl~dt35WG]V]。