A：which
B：of whose
C：whose
D：form which
① ____ A. duck B. chick C. clock
② ____ A. photo B. shape C. sheep
③ ____ A. who B. whale C. what
Jim with his parents ______ going to visit the Forbidden City ______ Sunday morning.
夏天清晨，小草上常出现晶莹的露珠，太阳出来后，露珠又悄然消失．则露珠的形成和消失过程的物态变化是（ ）
空气污染指数反映空气被污染的程度，指数越大，空气污染越严重．
