. Time lines can really help students to understand tenses. They provide visual reinforcement.
. There are no rules for time lines. Many teachers use a a wiggly line for the continuous to show action. Play with them and get your students to draw them too.
. How would you draw a time line for?
1. He goes swimming every day (Present Simple);
2. She's having a shower (Present Continuous).

. It can be difficult to for learners to hear whether the voice goes up or down at the end. Remember, to go up, the voice has to go down first, and to go down, it first has to go up!
. Sing the pattern (bah bah) and ask students to repeat that before they say the words. It makes it easier for them to hear the musical pattern of the phrase.

Here are seven more suggestions for your reference. Tick those that you like and do (or could do).
. Don't just play a recording a second time without showing students that they have understood something. When they say 'Nao entendimos nada!' ask easy questions like; What language was it? How do you know? How many speakers? Male or female? Who spoke most? Who was happy? In a hurry? Successful? What words/phrases did you catch? What do you think happened? to show how much they did understand, before listening again, with a new task.
. Don't play an extract again and again unless
1. it's very short (about 10 seconds), and
2. you're doing concentrated work on pronunciation, e.g. listen to a section from a song which they found really difficult to understand and would like to understand why.
. Use video/TV/DVDs as well as cassettes. Elicit and contrast the extra information provided by the visual element. The majority of listening is interactive and face to face, so lip-reading and interpreting gesture is a very important part of learning to listen.
. Set listening homework, e.g. the workbook tape, form a class listening club, listen to 'talking books' (novels on CD - e.g. www.learnenglish.org.uk), listen to tonight's film on TV or a song and remember 1 phrase, 3 words or whatever, to bring to class next time.
. Exploit the Internet, e.g. listen to www.bbc.co.uk/worldservice/learningenglish or www.lyrics.ch
. Have sts create their own listening tasks, e.g. leaving answerphone messages for each other, phoning or sending cassette messages to each other.
. Don't forget to do "listening for enjoyment" too to get students used to the "medium". For examples, play background music in class or watch sub-titled films, MTV, CNN, listen to an English radio channel, etc. so English enters their subconscious too.