He went home for lunch____ the clock struck twelve.
| A．while | B．immediately | C． right away | D．at once |
I made a promise to myself _______ this year, my first year in high school, would be different.
| A．whether | B．what | C．that | D．how |
Nothing is so easy as _____ parents to raise their expectations of their children too high.
| A．of | B．to | C．by | D．for |
The air quality in the city, ______ is shown in the report, has improved over the past two months.
| A．that | B．it | C．as | D．what |
Letterboxes are much more in the UK than in the US, where most people have a mailbox instead.
| A．common | B．normal | C．ordinary | D．usual |
When different cultures, we often pay attention only to the differences without noticing the many similarities.
| A．compared | B．being compared |
| C．comparing | D．having compared |