1 . His attention ________ (concentrate) on his experiment, so he had no time for his family. (所给词的适当形式填空)
→ ________, he had no time for his family. (with复合结构 )
→ ________, he had no time for his family. (独立主格结构)

2 . Read the sentences and explain why the passive voice is used.
1. A total of 28 men had been selected out of the applicants before Ernest Shackleton set out for Antarctica.
2. It is said that South Georgia had never been crossed by explorers on foot before Shackleton and his men’s expedition.
3. On 17 January 1915, the Endurance got stuck in ice. A lot of efforts were being made to solve the problem when the ice melted and the ship suddenly broke in half.

3 . Napping spaces are nothing new; places to rest have already been________ in other big cities in the world. (用“动词+up”型短语完成句子)