制汤时，也可先用大火烧开，撇尽浮末，然后根据具体制汤方法，改用中火或小火加热。
参考答案：对
U.S. President Barack Obama arrived in China’s economic center Shanghai on Sunday night, November 15th 2009, ______a state visit to China.
A．starting
B．started
C．to start
D．having started
场地至少应设（）个出入口。
A.1
B.2
C.3
