We were only able to make a rough estimate of how much fuel would be required.

我们只能对所需燃料的量作一个粗略估计。

《柯林斯英汉双解大词典》

We were only able to make a rough estimate of how much money would be required.

需要多少钱，我们只能做个大致的估计。

youdao

There is also no reliable way to determine the content of collagen in liver. The diagnose of liver fibrosis based only on a rough estimate has a limited applications.

另外，目前还没有可靠的办法确定肝组织胶原的含量，仅根据肝内纤维增生的情况进行大概的估计，具有一定的局限性。

youdao

The committee was told there were 37, 000 registered bee keepers in England and Wales - but as there was no compulsory registration, unlike in France and New Zealand - that was only a rough estimate of how many people actually kept bees.

BBC: Dying bees 'were not a priority'