自考《英语(二)》试题练习:填文补句(4.21)
单选题
【填句补文】 Although the researchers have only just made the technical details of the microscope public, it is already on sale. It is currently the size of a refrigerator and takes several minutes to scan a circuit, but Xiao and Schrag are working ________.
A、to take tiny chips we require
B、to making chips any smaller
C、to shrink it to the size of a desktop computer and cut the scanning time to 30 seconds
D、of conducting electricity