Large molecules can be broken down to releaseenergy. Alternatively, they can be formed to buildcellular structures or store information. Inbiological systems there are four major types ofchemical reactions involved in breaking apart andbuilding molecules:acid-base or neutralization reactions, whichtransfer hydrogen ions between molecules,redox, or oxidation-reduction reactions, whichtransfer electrons between molecules,hydrolysis reactions, in which molecules reactwith H2O […]
Single-Bonded Functional Groups
When you cut yourself, it is often a good idea to swab the cut with rubbing alcohol to disinfect it. Most rubbing alcohols that are sold in drugstores are based on 2-propanol (common name: isopropanol), C3H8O. You can also swab a cut with a rubbing alcohol based on ethanol, C2H6O. Often it is hard to […]
Who’s who in the office
Listen to two people talking about the people in their office to practise and improve your listening skills. Do the preparation task first. Then listen to the audio and do the exercises. Preparation Transcript Task 1 Task 2
Understanding an explanation
Listen to a professor’s explanation to practise and improve your listening skills. Do the preparation task first. Then listen to the audio and do the exercises. Preparation Trascript Task 1 Task 2
Transport announcements
Listen to some transport announcements to practise and improve your listening skills. Do the preparation task first. Then listen to the audio and do the exercises. Preparation Transcript Task 1 Task 2
Missing a class
Listen to a student explain why she can’t come to class to practise and improve your listening skills. Do the preparation task first. Then listen to the audio and do the exercises. Preparation Transcript Task 1 Task 2
The first English class
Listen to a teacher give students information about a new course to practise and improve your listening skills. Do the preparation task first. Then listen to the audio and do the exercises. Preparation Transcript Task 1 Task 2
Shopping for clothes
Listen to a conversation in a shop to practise and improve your listening skills. Do the preparation task first. Then listen to the audio and do the exercises. Preparation Transcript Task 1 Task 2
Organising a group project
Listen to people organising a group project and answer the questions to practise and improve your listening skills. Do the preparation task first. Then listen to the audio and do the exercises. Preparation Transcript Task 1 Task 2
testing
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