what"s on the screan?It there (an) ad for a new film.为什么不用the

what"s on the screan?It there (an) ad for a new film.为什么不用the
what"s on the screan?It there (an) ad for a new film.为什么不用the

what"s on the screan?It there (an) ad for a new film.为什么不用the
ad在句子中是初次提到.如果是再次提到同样的事物才用the.希望能帮到你,祝你进步.