However, the approximation error can be large under harsh lighting conditions, thus making it difficult to recover albedo information.

然而，在苛刻光照条件下，这种近似的误差往往比较大，以至于很难恢复出反射率信息。

youdao

Though W grade can be increased, it is difficult to better recover tungsten with mechanical beneficiation methods.

矿石中钨品位虽可得到提高，但采用机械选矿方法却难以较好回收。

youdao

However, as Red Sox outfielder Jacoby Ellsbury can attest to, rib fractures can linger and be more difficult to recover from than expected.

FORBES: Ten Ridiculous Baseball Injuries