wget好像不支持断点续传

-c
      --continue
          Continue getting a partially-downloaded file.  This is
          useful when you want to finish up a download started
          by a previous instance of Wget, or by another program.
          For instance:

                  wget -c ftp://sunsite.doc.ic.ac.uk/ls-lR.Z

另外，d4x也是可以的。