ou machine, you can either read the user’sguide for guidance or fax us for specific instruction. Don’t ______ thetrial-and-error method.

Even if there is no scientific proof secondhand smoke causes cancer, there is no reason why nonsmokers should be forced to take this risk.

When the reached the top of the hill, they _____ so they had to stop for a rest.

Long marks on the street ________ that the driver had attempted to brake

With a huge amount of food ________，all of the staff are busy preparing for the dinner tonight.