Глаголы в скобках поставить в нужную временную форму past simple или past continuous 1. the steam engine … (to appear) in 1763 2. i (not to go) out last night because it (to rain). 3. mendeleev … (to create) his periodic table in 1871. 4. they (to come) in when i (to have dinner) with my friend. 5. ecological problems … (to appear) in the xx century.
2) I didn't go out last night because it was raining.
3) Mendeleev created his Periodic Table in 1871.
4) They came in when I am having dinner with my friend.
5) Ecological problems appeared in the XX century.