1. Rulers are used to tell the length of objects.<br />2. Before you come in, you should knock on the door.<br />3. The old man is in trouble. Let's help him cross the street.<br />4. Yesterday we stayed in a four-star hotel and the service was nice.<br />5. The cartoon book is so special that children can draw lovely animals on it.<br />1. Rulers are used to tell the length of objects.<br />2. Before you come in, you should knock on the door.<br />3. The old man is in trouble. Let's help him cross the street.<br />4. Yesterday we stayed in a four-star hotel and the service was nice.<br />5. The cartoon book is so special that children can draw lovely animals on it.
B. 
C. 
E. 
F. 
G. 
