语法总结
现在完成进行时表持续研究
have been trying to find out 写医生持续努力、尚未结束的研究状态。
相似句：
- They have been searching for an answer for months.
- Scientists have been studying the disease closely.
prove to be
proved to be very difficult 用来客观评价事情最终呈现出来的样子。
相似句：
- The task proved to be harder than expected.
- The idea proved to be useful.
fear that ... would ...
feared that the mummy would fall to pieces 写出手术前的担忧。
相似句：
- She feared that the glass would break.
- They feared that the bridge would collapse.