21. With ______ successful launching of Tiangong-1, China’s space dream has taken ______ step closer to reality.
A. the; a B. /; a C. a; the D. the; /
22. _______ excited his parents most is that he had passed the entrance exam and was admitted into his dream college.
A. That B. What C. Which D. It
23. Maybe you could be an inventor ---- maybe even good enough to ______ an idea for the next iPhone or new medicine for cancer.
A. put up with B. keep up with C. catch up with D. come up with
