1. Since most if not all learning occurs through ______, relating one observation to another, it would be strange indeed if the study of other cultures did not also illuminate the study of our own.

　　A assumptions

　　B experiments

　　C comparisons

　　D repetitions

　　E impressions

　　2. Unfortunately, his damaging attacks on the ramifications of the economic policy have been ______ by his wholehearted acceptance of that policy's underlying assumptions.

　　A supplemented

　　B undermined

　　C wasted

　　D diverted

　　E redeemed

　　3. Exposure to low-intensity gamma radiation slows the rate of growth of the spoilage microorganisms in food in much the same way that the low heat used in pasteurization ______ the spoilage action of the microorganisms in milk.

　　A precludes

　　B initiates

　　C inhibits

　　D isolates

　　E purifies

　　4. As long as nations cannot themselves accumulate enough physical power to dominate all others, they must depend on ______.

　　A allies

　　B resources

　　C freedom

　　D education

　　E self-determination

　　5. Nearly two-thirds of the country's mushroom crop is produced by 160 growers in a single county, the greatest ______ growers anywhere.

　　A cause of

　　B agreement among

　　C indication of

　　D interaction between

　　E concentration of