Underline the correct word in bold. a. I have observed this

Underline the correct word in bold.
a. I have observed this phenomenon this week/last month.
b. They finished their experiment yesterday/already.
c. The lecturer has just/a minute ago turned our attention to static electricity. d. I have seen this article on Monday/hefore.
e. The companies signed an agreement on limiting greenhouse gases five days ago/recently.
f. Galvani observed that the legs of the dead frog jumped as a result of an electric charge during his experiments/ever.