1．(2011·南京师大附中月考)The price in different countries will be based________and local economic conditions.
A．in advance B．in conclusion
C．on demand D．at all costs
2．On the way________a book，he found some of his classmates________in the street.
A．to buy；knocking down
B．to buy；knocking about
C．to buying；knocking about
D．to buying；knocking into
