has been able to do是表示“已经能做”的意思吗?现在完成时的时态?

是“已经有能力做”“已经能够做”的意思,当然,“能够做”一定是说明他已经做过了.
No other governor has been able to do since John Connally in the early 60s.
自 60年 代 初 约 翰 · 康 纳 利 之 后 便 无 人 能 做 到 这 一 点 .
Thanks to the Chinese people's unrelenting and heroic struggle during the last hundred years,imperialism has not been able to subjugate China,nor will it ever be able to do so.
中国人民,百年以来,不屈不挠、再接再厉的英勇斗争,使得帝国主义至今不能灭亡中国,也永远不能灭亡中国.
"This film has been both a test and a personal triumph.It's a great feeling to do things I wasn't sure I was able to do,"said Maggie Cheung."
"这部片子是一次试验,我尝试做了一件最初没有把握的事.但最终证明我是成功的,这种感觉很棒.""张曼玉说."
The Singapore Arts Festival is the premier arts event here.Any group that has been invited to be part of it will be able to get a higher-than-usual sponsorship and will endeavour to do its best.
艺术节是新加坡最重要艺术盛会,无论哪个团体受邀参加,都是全力以赴,能争取到的赞助也比平常高.