A:cleaning
B:to clea
C:being cleaned
D:to being cleaned
A: Hello, Kate. ____
B: That's beautiful. I like it.
A: ____
B: I need four.
B: They're funny.
A: You can also buy a T-shirt for your friend.
B: ____
A. Good idea.
B. What about these caps?
C. Come and look at this cap.
D. How many caps do you need?
E. Let's go.
“化学为生命密码解锁”,“DNA”承载着生命遗传的密码,胞嘧啶(C4H5ON3)是DNA水解产物之一.