The equations, although difficult, are well-defined.

该方程，虽然困难，但却是明确界定。

youdao

Emotion, although difficult to control, but it is a powerful force.

感情虽然难以控制，但却是一种强大的动力。

youdao

This factor, although difficult to quantify, can be gauged using various metrics.

这项因素虽然难量化，可以被衡量使用不同的度量。

youdao

Although it is inevitably slower and more difficult than any of us would wish, we are mobilizing all resources as fast as we possibly can."

VOA: special.2010.01.16

She had a very difficult childhood although information about her early history is limited.

VOA: special.2009.06.07

And although the land seemed rich, it was difficult to prepare for planting.

VOA: special.2010.04.15

Although difficult economic conditions still exist in much of Europe, Mr. Yamada says Mitsui will be bolder this time.

WSJ: Mitsui Fudosan Has

Pollock's use of disguised and obscured representation, although later difficult to detect, persisted into his abstract masterpieces of the late '40s and early '50s.

WSJ: Men of Fire | Hood Museum | Becoming Jackson Pollock | By Lee Rosenbaum

Correspondingly, although often difficult, a resolution must be found.

FORBES: Post-Apocalyptic Municipal Bond Buying Guide