Grammar-Quizzes.com

CERTAINTY & DOUBT

Undoubtedly, he'll reach the top of the mountain.  (a sure guess)
certainly, decidedly, undoubtedly, definitely, most likely, very likely, quite likely, of course,
Perhaps, he'll reach the top of the mountain. 
probably, maybe, I guess, I think, I doubt, unlikely 
 

CERTAINTY & DOUBT

Without a doubt, he'll reach the top of the mountain.  (a sure guess)
certainly, decidedly, undoubtedly, definitely, most likely, very likely, quite likely, of course,
With luck, he'll reach the top of the mountain. 
With luck, without a doubt 
 

ACTUALITY AND REALITY

He actually climbed it by himself.  (factual, widely accepted)
Actually, he climbed it by himself.  (factual, widely accepted)
actually, truly,really,
 

ACTUALITY AND REALITY

In fact, he climbed it by himself.  (factual, widely accepted)
In other words, he did what no one had done before. 
in fact, in actual fact, in truth
 

VIEWPOINT OR PERSPECTIVE

Professionally, he's pretty amazing. (limiting it to my opinion)
officially, professionally, legally, morally, ethically, healthwise
 

VIEWPOINT OR PERSPECTIVE

From my view, he's pretty amazing. (limiting it to my opinion)
from my perspective, in my view, in my opinion,

SOURCE OF KNOWLEDGE

Apparently, he climbed it in world-record time.  (second-hand information)
Younger climbers, reputedly, are less strategic climbers.
evidently, apparently, reportedly, reputedly
 

SOURCE OF KNOWLEDGE

According to them, younger climbers are less strategic climbers.
according to  X
 

LIMITATION / GENRALIZATION

He mostly climbed it by himself.  (had some assistance)
Typically, younger climbers are stronger climbers.
mainly, typically, generally, largely
 

LIMITATION / GENRALIZATION

For the most part, he climbed it by himself.  (had some assistance)
On the whole, younger climbers are stronger climbers.
in most cases, in general, for the most part, on the whole
 

IMPRECISION

Rougly, he climbed it in four hours.  (about) 
about, roughly, so to speak, kind of, sort of

IMPRECISION

In a way, he had help from others.  He sort of cheated by taking a helicopter down. 
in a way,

assuredly / certainly

in fact

from my perspective

decidedly / definitely

really

in his view

necessarily / surely

actually

in our opinion

obviously / most likely

truly / truthfully / in truth

from a linguistic point of view

undoubtedly / undeniably

in actual fact

with respect to the law

very likely / probably

I mean

regarding the law

conceivably / maybe

that is to say

officially  (domain)

perhaps, possibly

in other words

economically

I guess / I doubt

legally / morally

unlikely

weatherwise (-wise adv)

expressing degree of certainty   

making things clear  

limiting the knowledge domain

evidently

in most cases

about

apparently

mainly

around

reportedly

typically

roughly

reputedly

generally / in general

so to speak

according to X

largely

kind of

for the most part

sort of

on the whole

in a way

in part

mentioning second-hand knowledge 

generalizing

roughly speaking 

In truth, we don't know how long the climb will take.

We truly don't know how long the climb will take.

Actually, we don't know how long the climb will take. /
*Really, …   (?  sounds awkward)

We don't really know how long the climb will take. /
We don't know really how long the climb will take.

Probably, the climb will take five hours.

The climb will probably take five hours.

In our opinion, the climb will take five hours.

The climb, in our opinion, will take five hours.

In fact, the climb will take five hours.

The climb, in fact, will take five hours.

In fact, the climb will take five hours.

The climb will take five hours.

*About, the climb will take five hours. (Use "Roughly, ")
 

  They expect the climb to take about five hours.