It is well known to all that a machine needs fuel to run;    ,man needs food to live on.

One car went too fast and_________missed hitting the other one.

I’m certain David’s told you his business troubles. _________, it’s no secret that he owes a lot of money to the bank.

—Must I turn off the gas after cooking ? —Of course . You can never be _______ careful withthat.

＿＿＿＿to my regret, I am unable to accept your warm invitation.