Minulý infinitiv v odborném textu

Distinguish: What causes the problem now?    x  What caused the problem?    (= in the past)
                       What may cause the problem now?   x   What may have caused the problem?  (=
in the past)

Ask these questions:

1.      Co způsobuje / může způsobit sesuvy
půdy?.....................................................................................

2.      Co způsobilo sesuv
půdy?.......................................................................................

3.      Co asi způsobilo sesuvy
půdy?.........................................................................

4.      Čím může být sesuv půdy
způsoben?.................................................................

5.      Čím mohl být sesuv půdy
způsoben?.................................................................

Practice the following sentence transformations:

Something may appear to be / not to be…  (=now)
1. In a landslide, it may appear that gravity is the only agent of erosion.
    In a landslide, gravity may appear
….................................................................

Something is unlikely to have happened. (= in the past)
1. It is not probable that gravity caused the rockslide.
    Gravity is unlikely …………………………………………………………………………

An agent (=a cause) must/could/may/might (not) have caused an event (=effect)

1.      Gravity probably did not  cause the rockslide. (=možná, že ne)
Gravity may not  …………………….…..…..the rockslide.

2.      It is obvious that gravity did not cause the rockslide.   (= určitě ne)
Gravity could not …………………..………………………….the rockslide.

3.      It is sure that gravity caused the rockslide.  (= určitě ano)
Gravity must …………………..…………………………...…….the rockslide.

An event (=effect)may/might/can/could be caused by…  =now)

1. It is possible that gravity starts the rockslide.
    The rockslide can …………………………………..gravity.

An event (=effect)may/might/can/could have been caused by…  =in the past)

1. It is possible that rainwater running off the mountainside started the rockslide.
    The landslide could …………………………………………………… rainwater.