Research on animal intelligence always makes us wonder just how smart humans are._____（1） the fruit-fly experiments described by Carl Zimmer in the Science Times. Fruit flies who were taught to be smarter than the average fruit fly_____（2）to live shorter lives. This suggests that_____（3）bulbs burn longer, that there is a(n) _____（4）in not being too bright.

Intelligence, it _____（5）, is a high-priced option. It takes more upkeep, burns more fuel and is slow_____（6）the starting line because it depends on learning—a(n) _____（7）process—instead of instinct. Plenty of other species are able to learn, and one of the things they’ve apparently learned is when to_____（8）.

Is there an adaptive value to_____（9）intelligence? That’s the question behind this new research. Instead of casting a wistful glance_____（10）at all the species we’ve left in the dust I.Q.-wise, it implicitly asks what the real_____（11） of our own intelligence might be. This is _____（12）the mind of every animal we’ve ever met.

Research on animal intelligence also makes us wonder what experiments animals would_____（13） on humans if they had the chance. Every cat with an owner, _____（14）, is running a small-scale study in operant conditioning. We believe that_____（15） animals ran the labs, they would test us to _____（16） the limits of our patience, our faithfulness, our memory for locations. They would try to decide what intelligence in humans is really _____（17）, not merely how much of it there is. _____（18）,they would hope to study a(n) _____（19）question: Are humans actually aware of the world they live in? _____（20）the results are inconclusive.