Perfect Tenses??

HEEEELLLLLPPPPPP! Eeep, I think my students need to study up on the perfect tenses. I think I'll have to do some more activities in class as well about these tenses. I had given my students an activity to do where they had to use the past perfect, the perfect and the future perfect tenses. I thought it was a pretty good activity. After we had finished writing out some sentences by passing around pieces of paper, the students had to email me their favourite or funniest sentences. The only problem was that when I opened my email this morning almost ALL of the sentences had huge mistakes in them in their use of the perfect tenses. Eeep. Okay, action time. I will have to think of something. In the meantime, here are three good sentences that my students sent me:

Before I was born, Scott had been born.

Since I was born, the economy of China has been developing very fast.

Before I die, at least one moonman will have travelled around the Earth.

Thanks to the people that sent me good sentences! Remember, if anyone needs help, please come and see me!