41
(A)came up with
(B)bumped into
(C)burst into
(D)plugged in

(A) came up with - 提出,提出了,想出
(B) bump into sb翻譯：與…不期而遇
(C) burst into. ph. 闖入 burst翻譯：（使）迸裂；（使）爆炸, （心中）充滿；心情迫切, 爆裂, 爆裂, 增加, （尤指短期的）突然增加；迸發。

(D) plug in中文:插入式的;插入;插換式;連接;插座

Leonardo da Vinci spent many unfruitful無效果 years, 39 his first stay in Milan and his second period in Florence, experimenting with a flying machine.

The attempt to support and move the human body in the air 40 because, in the absence缺勤；不在場, 不存在 of an internal combustion燃燒（過程） engine, Leonardo could not create mechanisms體制，結構方式 of propulsion推進；推動力 capable of providing the necessary upward向上的，朝上 lift升高.

Nevertheless不過，仍然；儘管如此, based on this understanding of air currents pressure, and resistance, he 41 designs for machines that anticipated預期，期望 the modern glider滑翔機, parachute降落傘, 跳傘, and helicopter.

Related to these studies were notes concerning the cosmos（視作有序體系的）宇宙, later developed by Galileo.