1. The order matters. He's declared his love for her. Now she must do the same (for the sake of the sentence). she loves him.
D
2. d again. It's the object form of the pronoun. (The pronoun that follows a verb).
3. This sentence has 2 correct meanings. If there really were exactly 1000, then a is correct. If there were many thousands then c is correct. I think I'd go with C if only 1 answer is allowed.
4. I can't make this one work. I suppose a is the closest. The second blank has to be an objective pronoun. Either her or him words. The first blank doesn't do much. If you change gives to give then you can definitely choose A. The subject is I which requires the singular of give. The second part of the sentence is (I) give them to him. Nothing else will work without correction.
A. <<<< for 4
5 A. I don't either.
6 D We always make the same mistake .... that they make.
