a series of difficulty ties difficulty

• 系列的困难

a series of difficulty ties difficulty的用法和样例：

例句

1. The local carmakers face a series of difficulties.
   本国汽车制造商面临一系列的困难。
2. The past few years have been especially difficult for the children's publishing industry despite meteoric successes, including the Harry Potter series.
   过去的数年对儿童书出版商来说是尤其的困难，尽管已经有了疾速的增长，其中包括哈利波特系列。