【明報專訊】MoMo has had back pain for a few days. She has no idea what caused it.

“ Dr Panda: MoMo, you may have muscle pain sitting that way. ”

“ MoMo: But I'm tired... ”

“ MoMo: Ouch! My back really hurts! ”

“ Bill: Are you all right? Did Eason attack you? ”

“ MoMo: No, I've been reading at home these days. ”

“ Dr Panda: I think your back hurts because your sitting posture is not good. ”

“ Dr Panda: If you sit for a long time, it is important for you to sit up straight! ”

“ Bill: Keeping your shoulders back helps preventing back pain too! ”

■English highway﹕ -sentences

Expressing reasons and purposes

When we want to introduce a reason, we may use ''as'', ''because'', or ''since''. When we want to introduce a purpose, we can use ''in order to'', ''in order that'', ''so'' and ''so that''.

e.g. As the food was very salty, we felt very thirsty.

e.g. Michael got up earlier today in order to have breakfast with his friends.

■Quiz

Rewrite the following sentences using the expressions in brackets.

(answers on next text)

1. What should I learn if I want to be a scientist? (in order to)

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2. I am sick. I can't attend the meeting. (because)

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3. It was too dark to go on. We camped here. (since)

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4. No one dared to go near the house which had a fierce dog. (so)

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5. It was freezing cold the night before. There was ice on the ground. (as)

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■Glossary

back (n) 背部

muscle (n) 肌肉

posture (n) 姿勢

prevent (v) 預防