I find that making students grasp the idea of interrogatives in a natural way is challenging. There is no corresponding structure in Portuguese and they have a hard time remembering to use the auxiliar verbs. I found two ways to burn the structure in their memory without using a long and boring grammar exposition lecture.
The first one is using flashcards. I have several printed verbs flashcards (which can be found throughout the web, here for example) which I give to my students to ask eah other questions. If I'm teaching Present Simple, I'll write a main question on the board ("How often do you...?") and the students need to ask each other the same question about each of the verbs. I let them speak freely for about twenty minutes, just observing and correcting when needed.
Another way I use is through a song called Eternal Flame by Atomic Kitten. It's an easy song that has some questions being asked and repeated several times in the lyrics. I give the students the lyrics with the questions erased and they have to listen and write them all down. The song is easy to follow and students usually end the class singing along. I also have a matching worksheet with some follow up activities.
You can find the song's lyrics and the worksheet under the cut.
( Eternal Flame WorksheetCollapse )