【单选题】PD Co is deciding whether to replace its delivery vans every year or every other year. The initial cost of a van is $20,000. Maintenance costs would be nil in the first year, and $5,000 at the end of...
【简答题】写出下列单词的复数形式。 1. There are a lot of_________ (drink) in the shop. 2. Lily and Lucy have a few_________ (difference). 3. The old man has no____(tooth). 4. _________ (hundred) of the students came to ...