我应该使用IF或ELSE IF作为第二个声明

I can't get this code to execute, I am sure that I wrote this incorrectly. Can someone assist please? Do you see something wrong?

if ($value1!=$value OR $value2 !=$value ) {
  echo "something ";
  exit();
}
else if ($value3!=$value OR $value4 !=$value) {
  echo "something";
  exit(); 
}

It's not clear what you're trying to do -- the comparisons between the variables and the variable names are not intuitive. That said, else is unnecessary here.

You only need else (or elseif) if you don't want the code in the else (or elseif) block to execute when the if statement is satisfied. Here, the if block contains an exit(). So, when the if condition is satisfied, no more code will be executed, regardless of whether it's in if or elseif blocks.

Some more detail:

Here's how if and else work:

if (condition) {
    // do this if condition is true
} elseif (condition_2) {
    // do this if condition is false but condition_2 is true
} else {
    // do this if neither condition nor condition_2 is true
}

/*
 * code here will execute whether or not either condition or condition_2 is true
 */

In your code, you short-circuit everything after the if block if the condition in your if is true. That is, if $value1!=$value OR $value2 !=$value, the script exits when you call exit();.