问题补充：
Dear Mr Smith,
Thank you very much for invite me to go and stay with 1.
you in Nanjing.It’s the most beautiful city,and I have been 2.
eager to see you again.So I’m very sorry to tell you that I can’t 3.
go this summer vacation,since I’ve already been promised 4.
to stay with my grandmother in the countryside.She has 5.
already 65 years old and miss me so much that I have no choice 6.
but do it.I’m busy preparing for my college entrance exams 7.
all these days and I feel quite sure of myself.I wish I can go, 8.
and see you and Tom at the end this year. 9.
Best wishes to both you and Tom! 10.
Yours sincerely,
Song Ping1.invite→inviting
答案：
(答案→)1.invite→inviting
解析：
1.invite→inviting介词后用v.-ing形式。
2.the→a此处没有比较的范围，用a most表示“一个非常……的”意思。
3.So→But从上下文语境分析，此处表示转折关系而非因果关系。
4.去掉been此处表示主动。
5.has →is此处用系动词，表示年龄。
6.miss→misses主语为单数第三人称。
7.do前加tohave no choice but to do sth.为固定结构。
8.can→could(wish→hope)wish后的宾语从句应使用虚拟语气。
9.this前加of短语at the end of“在……末尾”。
10.正确。
