135.Nearly all speed reading courses have a “pacing element”. This timing device lets the students know how many words a minute they are reading. A.

135.Nearly all speed reading courses have a “pacing element”. This timing device lets the students know how many words a minute they are reading. 
A. Nearly all speed reading courses have a “pacing element” which is a timing device lets the students know how many words a minute they are reading. 
B. Nearly all speed reading courses have a “pacing element” which is a timing device that lets the students know how many words a minute they are reading. 
C. Nearly all speed reading courses have a “pacing element”, a timing device that lets the students know how many words a minute they are reading.
  D. Nearly all speed reading courses have a “pacing element”, that is a timing device that lets the students know how many words a minute they are reading.
136. Now go back and read them at what you feel to be your normal w.p.m rate. You can comfortably understand at this rate. 
A. Now go back and read them at what you feel to be your normal w.p.m rate, the rate which you can comfortably understand. 
B. Now go back and read them at what you feel to be your normal w.p. m rate the rate at which you can comfortably understand.
  C. Now go back and read them at what you feel to be your normal w.p.m rate, the rate which you can comfortably understand at.
D. B and C are correct. 
137. Some students prefer a strict teacher. This teacher tells them exactly what to do.
A. Some students prefer a strict teacher, who tells them exactly what to do. 
B. Some students prefer a strict teacher who tells them exactly what to do. 
C. Some students prefer a strict teacher, that tells them exactly what to do.
D. All are correct. 
138. Many devices offer apps. These apps use voice recognition technology
A. Many devices offer apps whose use voice recognition technology. 
B. Many devices offer apps, which use voice recognition technology. 
C. Many devices offer apps which use voice recognition technology.
D. Many devices offer apps in which use voice recognition technology. 
139. This is my new tablet. It uses the latest digital technology.
A. This is my new tablet that uses the latest digital technology.
  B. This is my new tablet which uses the latest digital technology. 
C. This is my new tablet, which uses the latest digital technology.
D. This is my new tablet, that uses the latest digital technology. 
140. Most children aged 5 to 11 in England go to primary schools. These schools are largely co-educational. 
A. Most children aged 5 to 11 in England go to primary schools, which are largely co-educational. 
B. Most children aged 5 to 11 in England go to primary schools which are largely co-educational.
C. Most children aged 5 to 11 in England go to primary schools that are largely co educational.
D. Most children aged 5 to 11 in England go to primary schools where are largely co-educational.