The main conclusion was that modifications to the model were needed 

We also showed that the sensor sensitivity depended very little on the sensor diameter 

We finally obtained a curve showing the depth of penetration as a function of time

present (general condition)

simple past (restricted to your study)

Filtration produces a satisfactory result (in general) 

Use of the web-based environment provided the greatest saving in staff time and cost to the company (in this study)

a variety of expression is used!:

• the findings are restricted to...

• it cannot be determined from this data

• we cannot be certain...

• we are unable to determine...

• we acknowledge that this study is exploratory

Without further investigation, we are unable to determine the cause of this with any degree of certainty

The results obtained in simulation show excellent agreement with the corresponding experimental data

This is in discrepancy with the earlier conclusions of Järvinen [7] 

This corresponds to the findings of Eklund [15]

verbs indicating tentativeness :

• is possible

• is likely

• appears

• seems

• might

It is possible that these differences in quality will show up during prolonged use

It is highly likely that this could occur again

common constructions:

• should be + -ed

• could be + -ed

• would be + -ed

• must be + -ed

• we recommend

• X is recommended

• it is hoped that.....X may...

It should be noted that the security arrangements should be tightly controlled

Longitudinal studies of company practices could also be set up

It is hoped that benchmarking may become a higher priority within the institution 

Further study is recommended to compare results with types of plastics which were not included in this study