Meaning: "substitute" means something used in place of another thing.

Wrong options:

• substitue: It leaves out the "t". The right spelling is "substitute". Every letter must be correct to get the mark.
• substitution: "substitution" is a close word, but it ends in "ion". The speaker says "substitute", which ends in "e".

Correct answer: protection

Explanation: Listen again to "in fire protection systems". It comes after "fire", so you need a word for a thing that keeps fire away. The ending ion is easy to forget.

Meaning: "protection" means the act or thing that keeps something safe from fire.

Wrong options:

• protrection: It adds an extra "r". Write "protection". Only the exact spelling gets the mark.
• protections: "protections" has an extra "s" at the end. The speaker says "protection", with no "s".

Correct answer: substances

Explanation: Here you hear "Like the ozone-depleting substances". It comes after "the", so you need a word for more than one thing. Do not forget the s at the end for more than one.

Meaning: "substances" means different things or chemicals that make up something.

Wrong options:

• substanes: It leaves out the "c". Write "substances". Only the exact spelling gets the mark.
• substance: "substance" has no "s" at the end. The speaker says "substances", so write the "s".

Correct answer: represent

Explanation: The speaker says "Though they represent a". You need an action word that shows what they make up. Because they is more than one, do not add s at the end.

Meaning: "represent" means to make up or stand for part of a total.

Wrong options:

• represnt: It leaves out the "e". The right spelling is "represent". Every letter must be correct to get the mark.
• represents: "represents" has an extra "s" at the end. The speaker says "represent", with no "s".

Correct answer: potential

Explanation: You hear "their global warming potential is". You need a word for ability or power, so it ends in al. Watch the middle e and a.

Meaning: "potential" means the capacity or power to cause warming.

Wrong options:

• potental: It leaves out the "i". The right spelling is "potential". Every letter must be correct to get the mark.
• potentials: "potentials" has an extra "s" at the end. The speaker says "potential", with no "s".