... for “operands”), while the subexpressions of the conditional expression are the test expression, the thenexpression, and the else expression.There are three major classes of phrases in an EL program: ... product of the values of their subnodes. Then the root of the tree stands for (1+11)·10 = 120. But thereare many other possible meanings for this tree. If * stands for exponentiationrather than ... and < in the first example), keywords (then, else,and endif delimit the test, then, and else parts of the first conditional), orexplicit matched delimiter pairs (such as the parentheses and...