能够 (néng gòu) means to be able to or to manage to do something. 能 means able and 够 means sufficient or to reach. Together they form a more emphatic or formal version of 能 (néng) alone, often suggesting that a certain level or standard is reached. 能够 is slightly more formal than plain 能 and appears frequently in written Mandarin, speeches, and polite speech (能够参加真是荣幸, it is an honour to be able to attend).