Meaning: "evolving" means changing over time.

Wrong options:

• evolve: "evolve" is a close word, but it ends in "e". The speaker says "evolving", which ends in "ing".

Correct answer: gravitational

Explanation: You hear "detection of gravitational waves". It comes after "of", so you need a describing word for waves.

Meaning: "gravitational" means caused by gravity.

Wrong options:

• gravity: "gravity" is a close word, but it ends in "y". The speaker says "gravitational", which ends in "ational".

Correct answer: celestial

Explanation: Listen for "observe celestial phenomena". It follows "observe", so you need a sky-related describing word.

Meaning: "celestial" means from space or the sky.

Wrong options:

• celestials: "celestials" has an extra "s" at the end. The speaker says "celestial", with no "s".

Correct answer: invisible

Explanation: On the recording you hear "these invisible forces". It comes after "these", so you need a word for not seen.

Meaning: "invisible" means cannot be seen.

Wrong options:

• invisble: It leaves out the "i". Check the letters: "invisible". A small spelling mistake loses the mark.
• visible: This is the opposite meaning, not the correct word here.

Correct answer: constitute

Explanation: Listen again to "forces constitute the majority". It comes before "the majority", so you need an action word that means make up.

Meaning: "constitute" means make up or form.

Wrong options:

• constiute: It leaves out the "t". Write "constitute". Only the exact spelling gets the mark.
• constitutes: "constitutes" has an extra "s" at the end. The speaker says "constitute", with no "s".

Correct answer: exploration

Explanation: Here you hear "ongoing exploration of outer space". It follows "ongoing", so you need a word ending in ion for the activity.

Meaning: "exploration" means the act of looking into new places.

Wrong options:

• explore: "explore" is a close word, but it ends in "e". The speaker says "exploration", which ends in "ation".