A:where
B:which
C:what
D:that
-How long does it take your father ______ to work every day?
- About half an hour.
方程xx+1=12的解是____.
公元前5世纪的雅典,产生了苏格拉底和克里斯提尼这样的伟大的大演说家,造成这种现象的主要原因是