根据句意及首字母完成单词。（每空1分，共5分）
We can buy what we want in a big s__________.
Could you please show me the w__________ to the post office.
A tall tree is in f__________ of our classroom.
We really got a __________(惊讶) when we met each other in Indian last year.
It is too __________(困难的) for me to work out the math problem.