while doing sentence pattern I'am unable to identify which is complement and object clearly.

Question

I know that complement is the one which completes the sense of the sentence but for example
"floods cause destruction". in this sentence which is complement or object? why? explain .

Answer 1

There's a good explanation with examples here:
http://grammar.ccc.commnet.edu/grammar/objects.htm#complement

In your example, "destruction" is the direct object (aka, verb complement). It is not an object complement because it's not referring to a direct object; it IS the direct object. Do you see the difference?