1. "You can buy bread at the bakery". Correct
However, you could also say: "You can buy bread from the bakery". You can buy things �at � a shop, or �from � a shop.
2. "You can buy bread from the baker". Correct
However, you can not, (grammatically), say: "You can buy bread at the baker". You can buy things �from � a person, not �at � a person.
3. "There are salad and bread". Incorrect. Both objects, �salad � and �bread � are singular. "There is salad. There is bread" The verb �are � is plural, but the nearest noun is �salad �, which is singular, (even though it has several ingredients). Verb and noun must agree.
4."There is salad and bread". Correct
Both objects are singular. "There is salad and there is bread" The verb �is �, (singular), is nearest to �salad � (singular), so verb and noun are in agreement.
5. "There is a boy and two girls". Correct
"There is a boy. There are two girls" = "There is a boy and two girls". The verb �is �, (singular), is nearest to �boy �, (singular), so verb and noun are in agreement.
5. If the two clauses had been reversed, with �girls � followed by �boy� the sentence would become:
"There are two girls and a boy". Correct.
"There are two girls. There is a boy" = "There are two girls and a boy". The verb �are �, (plural), is nearest to �girls �, (plural), so verb and noun are in agreement.
Les Douglas