On the use of present simple and continuous, the business textbook I have (Market Leader) says the time expression "now" is used in the present continuous, but in the exercise below where "now" is used, it gives the answer with main verb "spend" in the present simple form "spends".
eBay ..... now [spend] $20m a year analysing suspicious sales.
The cases I have managed to see where "now" is being used in the present simple are all with state verbs like (have, hold and own) not dynamic ones like "spend". However, I used to think that now in contrast with the past could be used in the present simple tense regardless of the verb being stative or dynamic as in the contrived example below. Now I am not sure any more.
They used to make small cars, but now they manufacture all kinds of vehicles
According to the book's rules, the ebay exercise above with the adverb "now" calls for the continuous use. However, the answer uses the present simple and it feels okay to me especially with the yearly expenses. If the book's answer is correct then I would to see why. What is the justification anyway?
"Now" seems like "by some time" in the quote below with a yearly rate. However, present continuous in the passive form is used.
By 1907, 1.7 million toy animals were being made a year.
The Businees Pre-intermediate, Macmillan p.52
I do not trust the book because I have spotted some errors with tables containing grammar rules causing inconsistency in the meaning. For example, claiming the adverbial "at the moment" a common present simple and present continuous time expression. There are others but I have to go over the text again to list them.