Presen perfect continuous

Signal Words
In order to be able to lead your reader in the direction you want to go, you will have to use strong transitions in your writing. You can do that in several ways: by using entiresentences to connect one thought to another, entire paragraphs to give more background information, or simply a word or two to indicate your intentions.
This list of signals is from The New ReadingTeacher's Book of Lists, 1985 Prentice-Hall, Inc., Englewood Cliffs, NJ 07632. By E. Fry, D. Fountoukidis, and J. Polk.
1. Continuation Signals (Warning—there are more ideas to come):
and | also | another| again | and finally |
first of all | A final reason | furthermore | in addition | last of all |
moreover | likewise | more | moreover | next |
one reason | other | secondly | similarly | too|
with |   |   |   |   |
2. Change-of-direction signals (Watch out—we’re doubling back):
although | but | conversely | despite | different from |
even though | however | in contrast | insteadof | in spite of |
nevertheless | otherwise | the opposite | on the contrary | on the other hand |
rather | still | yet | while | though |
 3. Sequence signals (There is an order to these ideas): first, second, third | A, B, C | in the first place | for one thing | then |
next | before | now | after | while |
into (far into the night) | until | last | during | since |
always | O’clock| on time | later | earlier |
  |   |   |   |   |
 4. Illustration signals (Here’s what that principle means in reality): 
for example | specifically | for instance | to illustrate | such as |much like | in the same way as | similar to |   |   |
 
5. Emphasis signals (This is important): 
a major development | it all boils down to | a significant factor | most of all | a primaryconcern |
most noteworthy | key feature | more than anything else | a major event | pay particular attention to |
a vital force | remember that | a central issue | should be noted | a distinctive...