long ago / not long ago - earlier / a little while earlier

With these time expressions we are thinking about a definite or finished time in the past, so we wound normally use a past tense. Compare the following:

• When did Brenda phone? ~ Not long ago. About ten minutes ago, I think.
  
  
• Merlin was a wizard who lived long ago in the reign of King Arthur.
  
  
• Where's mum? ~ I don't know. She was on the computer writing an email a minute or two ago, but I don't know where she is now.
  
  
• They'll be here soon. Isn't it time you made the pudding? ~ I made it a little while earlier, before you came home.
  
  
• I had to go to Manchester earlier last week, so couldn't come to your lecture.

until / till midnight

We use both till and until as a preposition or conjunction to refer to something that happened up to a particular point in time. The particular point in time can be in the past or the future, so past tenses and a variety of future forms are both possible. Compare the following:

• I didn't get home until midnight last night. I'm leaving again now and I shan't be back until ten o' clock this evening.
  
  
• I was working for a building company until the end of 1999, then I went freelance.
  
  
• You must wait here in the waiting room until they call your name.
  
  
• I can't really diagnose your condition until I receive the results of the blood tests.
  
  
• I can't really tell you what's wrong until I have received the results of the blood tests.
  

expressions of finished time: past tenses

Note that with all expressions of finished time, like yesterday, the week before last, last month, ten years ago, in the Eighties, then, when, etc, past tenses are required:

• I was doing my shopping in in the supermarket yesterday when I bumped into my ex-wife whom I hadn't seen for five years.
  We got married in the Eighties - house prices were much lower then. Our son was born in 1988.

time-up-till-now expressions: perfect tenses

Note also that with time-up-till-now expressions like recently, lately, often, all day, this week, etc, and with for and since expressions, perfect tenses are normally required:

• I've been playing the piano for twelve years now - since I was six.
  
  
• I haven't seen much of Tom recently / lately. ~ No, I haven't either. I haven't seen him since that trip up the Thames last summer. I've often wondered how he's getting on now.
  
  
• I've been working all day today but I haven't done very much work this week.
  

in an hour

If we are referring to a past time situation, in an hour means within the hour in question:

• My boss thought it would take longer, but I completed the report in half an hour yesterday afternoon.
  
  
• He wrote the novel in six weeks last summer when he was on holiday in Florida.

If we are referring to a future situation, in an hour normally means after an hour has passed and can be used as the simpler alternative to in an hour's time. Compare the following and note how the preposition changes when we use a negative construction:

• It'll be ready in about half an hour.
  
• It'll be ready in half an hour's time.
  
• It won't be ready for half an hour.
  
  
• I'll see you again in six months.
  
• I'll see you again in six months' time.
  
• I shan't see you again for six months.