1. Since 1984 the sport has included in the olympic games as part of the yachting events.
Has included=> Has been included (thể bị động)
2. By the time joan arrived, all of the food had eaten
Had eaten=> Had been eaten (thể bị động)
3. The weather this year is much hotter than 2005
Than 2005=> than the weather in 2005
4. The final exam was the more difficult than the mid-semester exam.
The more=> More (dạng câu so sánh hơn, không có "the")
5. The custorms in his country are more traditional than that in the united states.
That=> the customs/they (từ that không thể thay thể cho the customs được)
6. Many optimist people have made prediction about the positive impact of the increasing mechanization on human life
Optimist=> Optimistic (trước danh từ nên từ này sẽ được chia dưới dạng tính từ)