1. This is his girlfriend and that is mine. 2. Our street is busier than their street. 3. These are her children

1. "This is his girlfriend and that is mine." translates to "Это его девушка, а то — моя." In this sentence, we are comparing two people"s girlfriends. The possessive pronouns "his" and "mine" are used to show ownership. "His" refers to the person we are talking about, while "mine" refers to the speaker"s girlfriend.

2. "Our street is busier than their street." translates to "Наша улица более оживленная, чем их улица." Here, we are comparing the level of activity or traffic on two streets. The use of the comparative form "busier than" indicates that our street has more activity than their street.

3. "These are her children and those are mine." translates to "Это ее дети, а то — мои." In this sentence, we are comparing two sets of children. "These" refers to the group of children we are currently talking about, and "those" refers to the other group of children. The possessive pronouns "her" and "mine" show ownership.

4. "Their flat is larger than my flat." translates to "Их квартира больше, чем моя." In this sentence, we are comparing the sizes of two flats. The comparative form "larger than" is used to indicate that their flat has a greater size than the speaker"s flat.

5. "It"s not your umbrella. It"s mine." translates to "Это не твой зонтик. Это мой." Here, we are comparing the ownership of two umbrellas. The possessive pronouns "your" and "mine" are used to show who the umbrellas belong to.

6. "Your telephone doesn"t work. Can I utilize your telephone?" translates to "Твой телефон не работает. Могу я воспользоваться твоим телефоном?" In this sentence, the speaker is asking if they can use the listener"s telephone since their own telephone is not working. "Your" refers to the listener"s telephone, and "my" is implied as the speaker is referring to their own telephone.

If you have any further questions or need more clarification, feel free to ask!