Unlike a heart attack , most strokes are painless .

不像突发心脏病，中风一般都是无痛的。

Both present as painless vision loss .

这两种情况均表现为无痛性视力下降。

The process will not be painless .

这个过程不可能无痛进行。

Britain 's own rebalancing has scarcely been painless .

英国自己重新调整几乎很少是无痛的。

But the procedure is safe and relatively painless .

但是这一过程却是安全且相对无痛的。