当空的英文：
high above in the sky

参考例句：

At noon the red sun is hanging in the sky.
中午赤日当空。

The water sparkled in the blazing sunlight, and there was not a boat in sight
此时毒太阳当空，河水耀着金光，一条游船也没有。

This spray was thrown up from the sea when the air rushed downwards under the hovercraft and struck the water.
当空气在气垫船下面急速冲击水面时，从海里卷起了浪花。

high是什么意思：
adj. 高的；海拔很高的；上层的；高尚的；十分赞同的；全盛的；有醉意的
n. 高水平，高气压，快感
adv. 在高处，音调高，（成本、价值）高

If you don't aim high you will never hit high
不立大志,难攀高峰

High level management position with high technology corporation.
高新术公司的高层管理职位

Mold manufacture has high risk and high affixation.
模具制造业是一个高风险与高附加值的行业。

This ore assays high in gold.
这矿石经检验证明含金量高。

The design is of very high standard.
设计质量很高。

sky是什么意思：
n. 天，天空

The sky is clearing.
天正明朗起来。

Sky is louring.
天空正变得阴沉。

After the storm the sky cleared.
暴风雨过后，天空明朗了。

And then, in the late afternoon the sky will clear,
然后，下午晚些时候天空变晴，

Stars glittered in a clear sky.
星星在晴空中闪烁。