但前提是

only if───只要……就；只是在……的时候；只有

butting in───n.紫铆素，紫铆黄酮；紫铆亭

button lift───上山牵引机，圆盘式拖牵

button up───按上，扣住；完成；守口如瓶

buttoned up───adj.守口如瓶的，沉默寡言的；圆满完成的

buttonless───adj.没有纽扣的

buttons up───按上，扣住；完成；守口如瓶

Agrillo's team found that mosquitofish can discriminate between numbers up to 16, but only if the ratio between the fish in each shoal was greater than 2:1.───阿格利罗的团队发现，食蚊鱼最多可以分辨大到16的两个数字的大小，但前提是每个鱼群中鱼的比例大于2:1。

I'll do that, but only if we set a few rules.───我可以干，但我们得定几条规矩。

The Chinese may very well on occasion be direct but only if no one, including themselves, will lose face.───中国人有时也可能比较坦率，但是只有当所有人不会因此而丢脸的时候，他们才会这样做。

It was a one-story structure, but only if you think of a Gothic cathedral as one story.

I'll tell you, but only if you don't tell anyone else.

Cook agreed happily, but only if he could follow the bus in his pickup truck.

But only if he beats Ivanisevic today and Courier loses his match with Chang.

This obviously saves time in group sessions, but only if everyone does it.

Schoolchildren are entitled to special equipment, but only if it is expressly provided for in their formal statement of needs.

Tamayo said he would, but only if Remba could invent a process that would allow them to have a relief-like dimensionality.

But only if you know the market well enough to avoid the pitfalls.

But only if the couple who have 7 children repay the outstanding capital immediately.