Исправленный e-mail:

Hi Marco,

Greetings from Italy! We were in Rome two days ago. Now we're in Florence. We're having a great time! Yesterday the weather was rainy, so it was a good day to visit the Uffizi. The Uffizi is a huge art museum. We were there for five hours. I was really tired last night. The last week we were in Venice. There weren't many tourists, so it wasn't very crowded. It's a beautiful city. Have a great summer, and please say hello to your family.

Todd

Объяснения исправлений:

1. before two days -> two days ago: "ago" используется для указания времени в прошлом относительно настоящего момента.
2. Yesterday the weather is rainy -> Yesterday the weather was rainy: Так как речь идёт о вчерашнем дне, нужно использовать прошедшее время глагола "to be" (was).
3. We was there -> We were there: С местоимением "We" глагол "to be" в прошедшем времени имеет форму "were".
4. yesterday night -> last night: "Last night" - это устойчивое выражение для обозначения прошлой ночи.
5. it weren't -> it wasn't: С местоимением "it" глагол "to be" в прошедшем времени имеет форму "wasn't" (сокращение от "was not").