英语单项选择和语法填空The new library will be __ only if they work day

英语单项选择和语法填空
The new library will be __ only if they work day and night.
A.affordable B.available C.favourable D.comfortable
-Where did you come across your wife?
-It was in the Lake District National Park __ we used to date.
这里为什么不能用that呢,不可以是强调句吗?
Word spread here and there __ the chemical factory near our school was pulled down.
这里可以用after吗?
第三题的答案好像是that，做word的同位语耶。