探究发现
1．To eat out was also a social activity.
2. ...it was not that difficult to make a simple and tasty dish.
3．It is hardest to give up the food that you grow up with.
4．Not that long ago, my first thought at mealtimes was to eat at a restaurant.
5．My plan is to invite my friends over at the weekend to show them my newfound skills.
[我的发现]
(1)句1中的不定式To eat out作主语；句2和句3中的it是形式主语，真正的主语是其后的不定式to make a simple and tasty dish和to give up the food that you grow up with；
(2)句4和句5中的不定式to eat at a restaurant和to invite my friends over at the weekend to show them my newfound skills都是作表语，放在系动词的后面。
