His attempt to ________the two friends failed because they had complete faith in each other.
句意：他离间那两个朋友的企图失败了，因为他们彼此完全信任。alienate使疏远；离间。abuse滥用；虐待。alleviate减轻，缓解。abandon抛弃。因此，本题的正确答案为A。