I blew it today.
I am currently participating in a special program through our University Extension service. They have partnered with a foreign chemical company. This company identifies talented high school students in its native country and hires them upon graduation. The students are sent to one of several partner schools in the US such as mine for 18 months of intensive English, study skills and introduction to basic technical courses (physics, calculus, and, oh, yeah, chemistry). Upon completion of the program, they enter various American universities for their undergrad degree in engineering before going back to work for the company.
I got these students in January to give them a very remedial introduction to freshman level chemistry. Some of these folks have had 3 years of high school chemistry already, but they learned it in their native tongue and by their native school system, which is very stringently rote learning. So learning a complex subject like chemistry in a new language with the critical thinking methods we use here can be a real challenge, hence the program.
When they started with me, they had been here a full year already, and are tired.