// 易错点3：忘记stack.length判断 → 访问stack[-1]会报错
Samsung has also upgraded image processing on its front-facing cameras with a new Object Aware Engine for improved portrait mode shots, hair textures and more accurate skin tones. Based on my early testing, images seemed sharper than on my older Samsung devices, even though this is (again) largely the same 12MP camera as last year.
，更多细节参见同城约会
可以断定，这风来自宇宙，来自地球四季轮替的铁律，尽管它悄然而至，却也挟带了无限辽远的信息：那是冰层坼裂的轰鸣，是万千根须在黑暗中摸索的窸窣，是无数生命在挣脱与拥抱之间那甜蜜的喘息。这春风，哪里仅是地理上的气流？它分明是时间本身最温柔的手，在徐徐推动着生的轮回。它将逝去的冬，酿成滋养新生的腐殖；它将枯寂的枝条，吹成待放的蓓蕾。在这永不停歇的循环中，生老病死的面目似乎并不那么可怖，它成了一个必要的休止符，一次深长的呼吸，一切的一切，无非都是为了下一句更嘹亮的歌唱。
We often compose multiple commands in a pipeline to make the most of our Effect system: