A．have covered three fifth B．have covered three fifths C．has covered three fifths D．has covered three fifth
单项选择题Goodbye, Mr. Smith. I'm very pleased ().
A．to meet you B．to have met you C．meeting D．having met you
单项选择题If you want(), you should speak slowly and clearly to the listeners.
A．to be understood B．to understand it C．understanding D．to understood
