He says it was accidental, but I think he did it ___ purpose. A. on B. by C. for D. with Explanation: The idiom is used on purpose for deliberate action.
We noticed the hidden garden only ___ chance. A. by B. on C. in D. with Explanation: The idiom is by chance for something discovered accidentally.
Emergency supplies should be kept close ___ hand. A. in B. on C. at D. by Explanation: The idiom is at hand for something nearby and available.
The receptionist is not ___ duty after 6 p.m. A. at B. in C. on D. under Explanation: The phrase "on duty" means someone is actively working.
Many low-lying farms are ___ risk when the river floods. A. in B. at C. on D. under Explanation: The phrase is at risk of being exposed to danger.
The ambassador accepted the award ___ behalf of the research team. A. on B. in C. at D. with Explanation: The phrase "on behalf of" is used when acting as a representative.
After the update, everything seems to be ___ control again. A. in B. under C. with D. by Explanation: The phrase is "under control" when a situation is successfully managed.
Students here study about five hours a night ___ average before finals. A. in B. on C. at D. by Explanation: The idiom is on average for a typical amount.
The sculpture is made of bronze; ___ fact, it only looks like stone from a distance. A. on B. at C. in D. by Explanation: The idiom is, in fact, for a true correction or clarification.
___ first, the plan sounded expensive, but it saved money later. A. At B. In C. On D. By Explanation: The idiom is "at first," meaning the initial impression.