I'm guessing here that you want to check your class' understanding of basic nouns?
Instead, then, of giving the explanation and asking, "Do you understand that?" you could try one of the following:
- writing a list of the words on the board and asking students to identify the fruit, the piece of furniture, the one you'd find in a supermarket, etc.
- getting students to rank the nouns in terms of size, shape, colour, etc
- get the students to match the words with the pictures
In other words, you are making sure that the students really understand what the words mean rather than just say they do!
There's an interesting article on concept checking here