1.
We know the electron to be a minute particle
____ an electric charge.
a)
having b) have c) to have d) has
2.
Substances through which electricity is easily
transmitted ____ conductors.
a)
call b) called c) are called d) being called
3.
These scientists continue ____ in this
promising field of knowledge.
a)
have
worked b) working c) being worked d) of working
4.
The
machine broke on account of its ____of poor material.
a)
have
been made b) having been made c) made d)
make
5.
Our galaxy ____ to be a spiral system.
a)
proved
b) prove c) is proved d)
is proving
6.
The
___ point of aluminum is 657°C.
a)
melted b) melt c)
melting d) melts
7.
____
Sun is known to have an 11-years cycle of activity.
a)
- b) a c) the d) an