西北地区的城市未排入前30名，其主要限制因素可能是

-------John and I will celebrate our fortieth wedding anniversary next month.

We are invited to a party _________in our club next Friday.

I felt so bad all day yesterday that I decided this morning I couldn’t face ________ day like that.

Whenever I met her, _________ was fairly often, she greeted me with a sweet smile.

The number of foreign students attending Chinese universities ________ rising steadily since1990.