again!!!!cloze passage 幫幫手

The first boats to be built were very small and simple. They were made of wood and paddles were used to make them move. The simplest boat
is made by tying a few logs together with rope-what is known as raft. This was the type of boat with which Huckleberry Finn, the famous storybook character, sailed down the Mississippi River. Other simple boats include the canoe and the small sampan.
But the building of ships changed when the sail was invented. Ships that used sails were bigger and could carry many more people. Also, such ships could travel much further. The English started to build many of these ships for military and trade purposes. They sailed to countries in Asia and exchanged gold for goods like tea which they brought back to England.
When the engine was invented, the design of ships was changed altogether.
Now, wood is no longer used to build ships but metal is used instead.
Even ships that can move under water-submarines-aew built. These ships do not depend on the wind to move, unlike the sail-ships. Hence they can go on journeys without relying on weather conditions. The lastest ships are even driven by nuclear petrol.

2010-01-02 10:34:21 補充：
完全同意 [你知道有那麼愛你的一個人的存在嗎﹏﹏﹏*] 君，在 "When the engine was invented, the design of ships was changed altogether" 這句中，"was changed again" 才是正確的，因為更吻合全文。

When the engine was invented, the design of ships was changed altogether

Should it be: was changed "again" instead?