Listen! My mother (sing)a song.

Listen my mother is singing a song

I need more context to answer this correctly but from what you have given me all i can say is "Listen! My mother (is singing) a song."

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).

the correct answer is b. so you can tailor your resumé to the position.

it is important before sending your resumé for you could add some extra information relating to former jobs that might you get a higher possibility to be hired.

may be the company is looking for an experienced person, and showing you have worked in the area they are looking a person for may give you more positive points!