Asoccer team is likely to score a goal at any time during a game . what is the probability it scores during the first half ?

Half. 

If a soccer team is going to score a goal with a probability of p, then p/2 will give the probability of scoring in the first half. 

This is simple enough to prove, since scoring in the first half and scoring in the second half are totally independent of each other, and equally likely.

I hope my answer has come to your help. Have a nice day ahead and may God bless you always!