Does anybody know the answer?

Which three events took place when lincoln lived at knob creek farm?

Christina rossetti's decision to have a robin, a bush, the moon, and the ocean speak in "a wintry sonnet" is an example of what? ?

1. in which sentence is the underlined portion a predicate nominative? for astronauts, going into space to repair orbiting equipment becomes a challenge. for astronauts, going into space to repair orbiting equipment becomes tricky. for astronauts, going into space to repair orbiting equipment becomes challenging. for astronauts, going into space to repair orbiting equipment becomes frequent.