A heavy dark cloud presaging rain or a storm.

U-Pb isotopic ages of 61 detrital zircon grains from the sillimanite-biotite-quartz schist of the Qinling Group in the North Qinling metamorphic terrane are reported in this paper. Of the 61 zircon grains, 15 were measured by SHRIMP ⅱ, and 46 by LA-ICPMS.

报道了北秦岭地块中秦岭岩群夕线黑云石英片岩61个碎屑锆石测点的207Pb/206Pb年龄测试结果，其中15个测点在SHRIMPⅡ上进行，46个测点来自LA-ICPMS的测定结果。

The second stage is the intrusion of medium to fine-grained biotite-K-feldspar granite.

第二阶段为中细粒黑云母钾长化岗岩。

There is a threat of rain in the dark sky.

黑云密布的天空有下雨的兆头。

Dehydration-melting experiment of the biotite-gneiss, eastern hebei, at 1 GPa pressure

冀东黑云母片麻岩在1GPa压力下脱水熔融实验

The black clouds indicate that it will rain soon.

黑云预示着快要下雨了。

Black clouds spilled ink half blotting out the hills;' pale rain bouncing beads that splatter in the boat.

黑云翻墨未遮山，白雨跳珠乱入船。（苏轼《望湖楼醉书》）

Here it is again in slow motion, the tornado hits the house, a black cloud then explodes hundreds of feet into the air.

现在又是缓慢前行，龙卷风袭击了房屋，乌云冲向几百英尺的高空。

The explosion caused a huge black cloud of dust.

火山的爆发造成了一大片黑灰云。

Watch the black cloud crawling nearer

看着黑色的乌云越来越近

Unexpectedly, a shroud of black cloud like a big mushroom rose in the distance immediately as if an atom bomb exploded.

没想到远处立刻升腾起蘑菇状的黑云（同原子弹爆炸一样的反应）

His unhappy face turned into a smile, and the black cloud that hung over his head turned into sunshine.

慢慢地，司机不高兴的脸变为笑脸，他头上的乌云变为阳光。

When the races were over, and we turned our faces homeward, one of the party noticed a black cloud drifting in from the sea, which grew and spread and thickened until it covered the whole sky.

就在比赛结束，我们正准备回家的时候，人群里有个人发现从海上飘来了一团黑云。这团黑云迅速地扩散增厚，直到遮蔽了整个天空。

This coincided with a black cloud which suddenly veiled the sun.

这时一团乌云忽然遮住了太阳。

After school I wanted to buy some Cn food from CNT but I changed my mind when I saw the black cloud all over the sky.

放学后我想从唐人街买一些中国食品，但是当我看到天上黑压压的乌云的时候，我改变了主意。

Before he could picture the rickshaw, this other thing would stealthily slip out to occupy his mind like a black cloud, obscuring the sun.

还没想到车，这点东西已经偷偷的溜出来，占住他的心，像块黑云遮住了太阳，把光明打断。

Brother Tianshuo, is a beetle-browed and plump black cloud.

朔哥，是一朵喜欢皱着眉头的胖乎乎的乌云。

And yeah, the black cloud faded a little bit, but so did all the work, because I was just floating along.

乌云似乎有点消散了，但工作也是，因为我如坠云中。

The entire top of the mountain exploded, and a huge black cloud rose into the air.

整个山顶爆裂开来，一团巨大的黑云升入空中。

While I knew I shouldn't let it, the mailman's morning delivery of another rejection letter for an article I'd submitted to a magazine made me feel like a black cloud of failure hung over my head.

虽然我知道自己不该这样，但是早班邮差送来的又一封我给杂志投稿的退稿信就象是一片失败的乌云挂在我的头顶上。

Black cloud says the party's over!

乌云说派对结束了！