There's a huge amount of variation in present-day dogs.现代的狗类有着数量众多的变种

huge amount of:大量的

They spent a huge amount of money on that villa.

他们花巨款买下了那幢别墅。

The Sun produce huge amount of energy.

产生如此巨大能量的原因。

then that may have been slightly selected upon to create与其他狼共同繁衍,然后就此轻微地影响了物种的进化

upon:紧接着；逼近

Upon his release, Davis went immediately to his mother.

戴维斯一被释放就立即回到了母亲身边。

Christmas is almost upon us again.

圣诞节又快到了。

词汇搭配:

act upon按照

upon condition that如果

agree upon就 ... 达成一致...

once upon a time从前

upon that于是