Tenses Worksheet

Fill in the blanks with an appropriate verb form.

Researchers in the US …………………….. (invented / have invented) a new panel which can harness solar energy even at night. The new approach ……………………….. (uses / is using / used) a special and economical manufacturing process to stamp tiny square spirals of conducting materials called nano-antennas onto a sheets of plastic. Each interlocking nano-antenna is as wide as 1/25th of the diameter of human hair. Because of their small size, the nano-antennas ……………………… (absorb / absorbing / absorbed) energy in the infrared part of the spectrum, just outside the range of what is visible to the eye.

 The sun ……………………… (radiates / radiating / radiate) a lot of infrared energy, some of which is ………………………… (absorb / absorbed / absorbing) by the earth and later released as radiation for hours after sunset. Nano-antennas can take in energy from both sunlight and the earth’s heat. And they are more efficient than conventional solar cells. The miniscule circuits ……………………. (absorb / absorbs / absorbed) energy just like the antenna on your television or in your cell phone.

Answers

Researchers in the US have invented a new panel which can harness solar energy even at night. The new approach uses a special and economical manufacturing process to stamp tiny square spirals of conducting materials called nano-antennas onto a sheets of plastic. Each interlocking nano-antenna is as wide as 1/25th of the diameter of human hair. Because of their small size, the nano-antennas absorb energy in the infrared part of the spectrum, just outside the range of what is visible to the eye.

 The sun radiates a lot of infrared energy, some of which is absorbed by the earth and later released as radiation for hours after sunset. Nano-antennas can take in energy from both sunlight and the earth’s heat. And they are more efficient than conventional solar cells. The miniscule circuits absorb energy just like the antenna on your television or in your cell phone.