作业精灵老师示例：
S1：How do I get to the farm？
S2：Walk along the Park Road and turn right. After that, you can
walk along the Green Street, turn left at the second crossing. You
can see the farm on your right.
S1：How do I get to the river？
S2：Walk along the Park Road and turn right. After that, you can
walk along the Green Street. Then, turn left and walk along the Orange
Street. You can see the river on your left.
S1：How do I get to the lake？
S2：Walk along the Park Road and turn right. After that, you can walk
along the Green Street. Then, turn left and walk along the Orange Street.
Turn right and walk along the Pink Street. The lake is on your right.
