To rack their brains

This afternoon, while I was teaching classes 316 and 314, coming upon the word "interpret," I mentioned an additional meaning of the word--to translate orally. To give the word life, I asked the students to interpret an English sentence into Taiwanese: I'm busy today and can't take any more work. Class 316 had a hard time with the second half, while class 314 interpreted the whole sentence almost fluently. Then when we moved on to the example sentence of the word "interpretation": Scientists were puzzled about what interpretation to give to certain patterns on the surface of the planet Mars, I asked Class 314 to interpret it again into Taiwanese. Yi-chin (怡晴) racked her brains and did the job. During the process, I knew she mistook the word "certain" for "correct." Afterwards, I asked her to recall the English version of the sentence without looking at the book. She did a good job. My conclusion is that things you try hard to figure out will be easier to recall.