Chữa lỗi sai trong câu

Chữa lỗi sai trong câu:

The first time they saw the ocean, they have never been to the beach before
Sarah has started learning piano 3 years ago
The last time we visited our grandparents was last year, and we not seen them since
The first time Jack eats sushi was amazing; he has never tasted anything like it before
The team has been working at this project for five months when they received a promotion
The last time she saw a concert was in 2019, but she has not gone to any concert since
The first time they travel abroad, they were really excited
Tom started to learn Spanish since 2 years
The last time we went hiking was 2 months ago, and we have not gone since
The first time Emma tried ice cream was in her childhood; she never tasted anything similar after that