If there are natural resources in a country, it is common for it to export some of them.
Professor Jordon is well known for his _____ into the habits of the common housefly.
. I support your decision, but I should also make it clear that I am not going to be _____ to it.
John _____ knowledge of radio just by staying around the radio station.
They did not find _____ to prepare for the worst conditions they might meet.