In english some verbs do not take continuous tenses: to seem, to know etc. IE we cannot say: I am knowing something. Those verbs are called stative, as they describe a state rather than an action. Some verbs, like "to see", are partially stative and can take continuous tenses only with certain meanings. For ex: I am seeing Scarlett Johansson (meaning I am dating SJ). English grammar does not allow us to say "I am seeing a bird" because it is a stative action, smth that happens momentarily. Unless the bird has very big breasts.
Only masculine singular distinguishes the accusative from the nominative (in the third person) -- the accusative case form looks like the nominative for feminine and neuter nouns (and third-person pronouns) in the singular, and always in the plural (again, for nouns and third-person pronouns).
Hi ElenaGromo2. When you are "seeing" someone, it is taken to be more of an intimate relationship, eg a courtship. You could also be seeing your doctor or your physiotherapist etc. However in this case where "he sees her" (or he sees them) it tells of a situation where he can actually see or spot her (or them), eg "he can see her/them in the shopping mall crowd" or he sees them in a restaurant. I hope this distinction helps to clarify your query. To be seeing somebody in a relationship, it would be a Verabredung, eg "Sie hat eine Verabredung mit ihrem Freund".
So, what do you do with, "Sie sieht sie"? She sees her; they see them; they see her; or she sees them? And don't say 'context' because that'll never show up in this sort of comment. Somebody seeing an exchange between two groups could have all those meanings - but how do native Germans make clear which thing they mean??
Hi Tom442002. "Sie sieht sie" can mean "She sees her" (in the accusative case) or "She sees them" (also in the accusative case). Although you didn't want the context to be brought into the equation, but the context would tell more precisely whether we are referring to a singular person (her) or to plural persons (them). It cannot mean "They see her" or "They see them" because how the verb is conjugated makes it incorrect. If it was meant to be "They see her" then it would have to be written as "Sie sehen sie". The verb would remain in the infinitive. Please also note that "sie" can be used to designate a female noun when not referring specifically to a person or an animal, eg "Wo ist meine Jacke - Sie liegt auf dem Tisch"! On the other hand, please remember that the capitalized Sie means formal You. I hope the above helps somewhat.