When a word ends in a consonant sound and the next word starts with a vowel the words link together. The ending consonant "jumps over" to the next word.

So when students hear this simple sentence, what they hear is:

This is one of the trickiest problems when listening to English. A basic listening skill is being able to pick out words, being able to understand words as words; being able to understand where the word boundaries are; where words start and finish. Liaison, the way English links together makes this tough. 

Teach your students about liaison. It might not help them suddenly "hear" all words and word boundaries, but it will help them understand. Students need to be given guidance. Not all teachers do this and not all textbooks do this.

Top-Up Listening teaches this. You should too.

Letting your students know about this linking will help their listening.