The hazards of oil drilling were demonstrated when an oil rig in the north sea exploded. this sentence is a) simple b) compound c) complex d) compound-complex

The sentence is c)

A complex sentence

The sentence is complex because it has a dependent clause (when an oil rig in the North Sea exploded) introduced by the subordinating conjunction when and it is joined to an independen clause:

[The hazards of oil drilling were demonstrated (when an oil rig in the North Sea exploded.)]

The sentence (when an oil rig in the North Sea exploded) is thought to be a dependent clause because it does not contain a complete thougth or idea, and it is related to the independent clause, which in turn, represents a complete idea and can stand on its own. In other words, the independent clause does not require futher information because it is complete.

covert: hidden or secret

candid: truthful and straightforward

what i get from these phrases is covert means undercover or underground and that's where the flower is in april. on the other hand, may is the month where flowers start to bloom and thats the reason why candid is being used as a word to describe the blossoming period of a flower.

hope this answer you.