For most informal dinners, you should wear comfortable and ______ clothes.
A．official B．formal C．casual D．proper
Johnson would have faced the music but he ______ doing things like that.
A．had stopped B．stopped C．was stopping D．has stopped
How can they learn anything ______ they spend all their spare time watching television?
A．when B．though C．while D．before
In this section, we will briefly describe possible ways of reducing the costs and risks ______ in doing this.
A．involving B．involved C．to involve D．being involved
This practice satisfies people of high moral standards psychologically and materially and ______ encourages other people’s enthusiasm.
A．on the contrary B．in the meantime C．from time to time D．all at once
______ city in Zhejiang Province, located on the river’s upper reaches, is believed to be ______ source of the dead pigs.
A．The; a B．The; the C．A; the D．A; a
